OCR GCSE Physics Revision
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OCR GCSE: Physics A (Gateway Science) (J249)
Exam years · 2027Specification version · Version 5.0 (July 2026)
Course details
OCR · GCSE PhysicsJ249Exam years · 2027
Assessment The assessment includes Paper 1 and Paper 2; see the official specification for the full structure.
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Reviewed course guidance
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Topic group
P1 Matter
- Core
Scope: Core · §2c P1.1a–f, P1.2a–f and P1.3a–b; mathematical outcomes PM1.1i and PM1.2i–ii
Open revision guidance
What to know
- P1.1a — Atomic models change when evidence rules out an earlier picture. Thomson's cathode-ray evidence supported electrons in diffuse positive matter; Geiger and Marsden's alpha-scattering observations, interpreted by Rutherford, implied a tiny concentrated positive nucleus; Bohr proposed electrons in specified energy levels.
- P1.1b — A tiny positive nucleus is surrounded by negative electrons. Nearly all atomic mass is concentrated in the nucleus, whose radius is much smaller than the atom's; the electron region determines most of the atom's radius.
- P1.1c — Atoms and small molecules are typically of order 1 × 10⁻¹⁰ m in size; this is an order of magnitude, not an exact size for every species.
- P1.1d and PM1.1i — Density is mass per unit volume: ρ = m/V. The SI unit is kg/m³; 1 g/cm³ equals 1000 kg/m³.
- P1.1e — Solid particles are close and vibrate about positions; liquid particles remain close but move past one another; gas particles are widely separated and move freely. These arrangements change mass per volume, so a gas is usually much less dense than the same substance as a solid or liquid.
- P1.1f — When mass is conserved, density changes inversely with volume: for fixed m, ρ = m/V. A sample that expands has lower density; mass does not disappear merely because volume changes.
- P1.2a — Melting, freezing, evaporation, condensation and sublimation are physical changes of state. In a closed sample, particles are rearranged, so total mass remains constant.
- P1.2b — A physical change can be reversed so the material recovers its original properties; a chemical change forms different substances and is not reversed simply by restoring the original shape or state.
- P1.2c — Heating transfers energy into a system and changes internal energy. Within one state it raises temperature; during a change of state energy changes particle arrangement/separation while temperature remains constant until the transition is complete.
- P1.2d — Specific heat capacity c is the energy needed to raise 1 kg by 1 °C without a state change, in J/(kg °C). Specific latent heat L is the energy needed to change the state of 1 kg without changing its temperature, in J/kg; fusion and vaporisation refer to different transitions.
- P1.2e and PM1.2i — For heating without a state change, ΔE = mcΔθ; energy is proportional to mass, specific heat capacity and temperature change.
- P1.2f and PM1.2ii — For a state change, ΔE = mL. Use the latent heat of the specified transition; do not include ΔT.
- P1.3a — Gas molecules move randomly. Their motion links temperature to average kinetic energy; collisions with container walls transfer momentum and create pressure, which is force per unit area.
- P1.3b — At fixed volume, heating makes molecules move faster and collide more often and forcefully with the walls, so pressure rises. Cooling reverses the trend; this shared-tier statement is qualitative.
What to do in an assessment
- Calculate density from measured mass and volume with consistent units. Example: 200 g in 80 cm³ gives 2.5 g/cm³ = 2500 kg/m³; for a conserved mass, compare the new volume before recalculating density.
- Choose the thermal equation from the process: 0.50 kg warmed by 8 °C at c = 4200 J/(kg °C) gains 16 800 J; 0.20 kg melting at L = 334 000 J/kg absorbs 66 800 J.
- Explain an atomic-model change as observation → inference → revised model. Explain gas pressure as particle speed/collision change → wall force change → pressure change; do not claim particles expand when heated.
In plain language
Evidence builds atomic models; particle arrangement explains density and state changes; energy either raises temperature or changes state, while gas collisions explain pressure.
Self-check
A 0.40 kg sample is heated by 5 °C and has c = 900 J/(kg °C). How much energy is transferred, and why is the latent-heat equation not used?
Show the answer
ΔE = mcΔθ = 0.40 × 900 × 5 = 1800 J. The sample changes temperature without changing state, so use specific heat capacity, not latent heat.
- Core
Scope: Core · §2c P1.3c–d, P1.3f–g and † mathematical outcome PM1.3i (shared-tier)
Open revision guidance
What to know
- P1.3c — Gas pressure is the force per unit area produced when moving gas particles collide with a surface. The force acts perpendicular to that surface.
- P1.3d — At constant temperature and fixed gas amount, increasing volume reduces pressure: particles collide with the walls less often.
- PM1.3i — For a fixed amount of gas at constant temperature, pV is constant, so p₁V₁ = p₂V₂.
- P1.3f–g — Atmospheric pressure is caused by the weight of air above a surface. It decreases with altitude because less air lies above and the overlying column weighs less.
What to do in an assessment
- Explain a pressure change through collision frequency and force per area; for atmospheric pressure, compare the weight of the air column above different heights.
- Use p₁V₁ = p₂V₂ only when gas amount and temperature are fixed. For 0.30 m³ at 100 kPa compressed to 0.20 m³, p₂ = 100 × 0.30/0.20 = 150 kPa.
In plain language
Gas particles create pressure by hitting surfaces; for a fixed gas amount at constant temperature, pV stays constant. Atmospheric pressure comes from the weight of the air above.
Self-check
Why is atmospheric pressure lower on a mountain than at sea level?
Show the answer
There is less air above the mountain, so the overlying air column has less weight per unit area.
Topic group
P2 Forces
- Core
Scope: Core · §2c Topic P2, P2.1a–h, P2.2a–q and P2.3a–o
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- Describe motion using distance, displacement, speed, velocity and acceleration; distance–time and velocity–time graphs show different features, and gradient or area has a defined physical meaning.
- A resultant force changes motion. Newton's laws connect resultant force, mass and acceleration; weight is the gravitational force on a mass, and mass is not weight.
- Contact and non-contact forces can balance or be unbalanced. Friction and drag oppose motion, while elastic deformation and momentum changes provide further models for force effects.
What to do in an assessment
- Read graph axes and units before finding a gradient or area; state what the calculated value represents.
- For a motion explanation, distinguish velocity from speed and identify the direction of the resultant force.
In plain language
Use forces to explain changes in speed or direction, and use motion graphs and equations to describe those changes quantitatively.
Self-check
What does a horizontal section on a velocity–time graph mean?
Show the answer
The velocity is constant, so the acceleration is zero during that interval.
- Core
Scope: Core · §2c P2.1a–e and P2.1g–h; mathematical outcomes PM2.1i–iv
Open revision guidance
What to know
- P2.1a — Measure a straight-line distance with a ruler or tape and time an event with a stopwatch, light gate or video; state the start/end points and repeat timing where reaction time matters.
- P2.1b — A distance–time graph records position/distance against time; its gradient gives speed. Obtain distance and elapsed time from the graph, then calculate speed rather than reading a slope as a distance.
- P2.1c — A rate is a quantity divided by time. Convert units before calculating: 72 km/h = 20 m/s because 72 ÷ 3.6 = 20; 1 cm = 0.01 m.
- P2.1d — Distance and speed are scalars (magnitude only); displacement and velocity are vectors (magnitude and direction). Distance is total path length, whereas displacement is the straight-line change from start to finish.
- P2.1e — On a distance–time graph, a steeper gradient means greater speed and a horizontal section means stationary. On a velocity–time graph, gradient is acceleration; a negative velocity indicates motion in the opposite direction.
- P2.1g — Average speed for non-uniform motion is total distance divided by total elapsed time, not the arithmetic mean of speeds unless the time intervals justify that operation.
- P2.1h and PM2.1i–iii — Use s = vt for uniform speed, a = (v − u)/t for uniform acceleration and v² − u² = 2as when time is not given. Here u/v are initial/final velocity and acceleration is signed.
- PM2.1iv — Kinetic energy is Eₖ = ½mv². Doubling speed quadruples kinetic energy for unchanged mass.
What to do in an assessment
- For 150 m travelled in 12 s, average speed is 150/12 = 12.5 m/s. For a velocity change from 4 to 16 m/s in 6 s, acceleration is (16−4)/6 = 2 m/s².
- Read axes, units, direction and scale before calculating a gradient or area. For a triangular v–t section rising to 10 m/s over 4 s, displacement is ½ × 4 × 10 = 20 m.
- For acceleration calculations, choose the equation from the known variables, convert km/h to m/s when needed, substitute with signs and units, and check whether the result describes speed, velocity or acceleration.
In plain language
Motion is measured with distance and time, while graphs show how motion changes. Direction matters for vector quantities and graph gradients or areas have specific meanings.
Self-check
A runner covers 300 m in 50 s, then 200 m in 40 s. What is the average speed for the whole journey?
Show the answer
Total distance is 500 m and total time is 90 s, so average speed = 500/90 = 5.56 m/s (3 s.f.).
- Core
Scope: Core · §2c P2.2a–d, P2.2i and P2.2l–p; shared mathematical outcomes PM2.2i and PM2.2iii–iv
Open revision guidance
What to know
- P2.2a — Objects interact through contact forces (normal contact and friction) or at a distance through gravity, electrostatics and magnetism.
- P2.2b — A force interaction involves a pair of objects: each exerts a force on the other. Identify both objects and both forces instead of describing a force as belonging to only one object.
- P2.2c — A force is a vector. Draw its arrow in the direction of its action and make arrow length proportional to magnitude when the scale is stated.
- P2.2d — Newton's first law: with zero resultant force, an object stays at rest or continues at constant velocity. A resultant force is needed to change velocity, not to maintain steady motion.
- P2.2i and PM2.2i — Newton's second law gives F = ma for resultant force. Increasing mass reduces acceleration for a fixed resultant force; increasing resultant force raises acceleration for a fixed mass.
- P2.2l — For a fixed change in momentum, a longer collision or stopping time means a smaller average resultant force. Vehicle safety features such as crumple zones and airbags extend the time over which momentum changes.
- P2.2m and PM2.2iii — Work done W = Fd when displacement d is along the line of action of the force. Work transfers energy to or from the object; if force and displacement are perpendicular, that force does no work along the displacement.
- P2.2n — Work and energy are both measured in joules; 1 N m = 1 J. Track energy stores and transfers, including kinetic or gravitational potential energy, and convert units before comparing.
- P2.2o and PM2.2iv — Power P = E/t = W/t is the rate of energy transfer or work done. The same energy transfer in less time means greater power.
- P2.2p — Newton's third law: if object A exerts a force on object B, B simultaneously exerts an equal-magnitude, opposite-direction force on A. They do not cancel because they act on different objects.
- Equilibrium has zero resultant force and no acceleration; in non-equilibrium, a non-zero resultant force changes velocity in its direction. For action–reaction pairs, the equal and opposite forces act on different objects and therefore do not cancel on one free-body diagram.
What to do in an assessment
- Draw a free-body diagram first, resolve forces along the relevant axes, then use the resultant in F = ma. Example: a 4 kg trolley with a 12 N resultant accelerates at 3 m/s².
- For impact-force explanations, describe qualitatively how increasing stopping time reduces the average force for a given momentum change; numerical momentum p = mv is Higher-only PM2.2ii and is taught in J249:higher-p2-force-outcomes. For work, use only the force component along displacement.
- Calculate power by dividing transferred energy by elapsed time. A 600 J transfer in 3 s is 200 W; show the joule and second units.
In plain language
Forces are vector interactions. Their resultant changes velocity; momentum, work and power quantify motion and energy transfer.
Self-check
A 4 kg trolley experiences a resultant force of 12 N. What is its acceleration?
Show the answer
Using F = ma, a = F/m = 12/4 = 3 m/s². This is the shared-tier resultant-force calculation PM2.2i.
- Core
Scope: Core · §2c P2.3a–i; mathematical outcomes PM2.3i–iv
Open revision guidance
What to know
- P2.3a — Stretching, bending or compressing an object requires forces that act in opposing directions; one force alone would accelerate the object rather than hold it deformed.
- P2.3b — Elastic deformation is reversible when the force is removed; plastic deformation leaves a permanent change in shape.
- P2.3c — For a spring in its linear region, extension grows in proportion to applied force. A force–extension graph is straight through the origin while the proportional relationship holds.
- P2.3d — A linear relationship has a constant ratio/gradient; a non-linear force–extension graph changes gradient, so each added force produces a different extra extension.
- P2.3e and PM2.3i — Spring constant k is force per extension: F = kx. A stiffer spring has a larger k; use extension from the original length, not total length.
- P2.3f and PM2.3ii — Work done stretching a spring is energy stored elastically. It equals the area under the force–extension graph; for a linear spring, W = ½Fx = ½kx².
- P2.3g — Every mass has a gravitational field that attracts other masses. More massive objects create stronger fields; field strength generally decreases with distance.
- P2.3h and PM2.3iii — Weight W is the gravitational force on an object, measured in newtons with a force meter. W = mg, where g is gravitational field strength (about 10 N/kg at Earth's surface); mass in kg is not changed by location.
- P2.3i and PM2.3iv — Near Earth's surface, freely falling objects accelerate at about 10 m/s² when air resistance is negligible. Gravitational potential energy near Earth is Eₚ = mgh, with h measured vertically.
What to do in an assessment
- Measure spring length before loading, add known masses in safe increments, convert each mass to force using W = mg, record extension, and stop before permanent deformation. Repeat readings and plot force against extension.
- Find k from the straight-line gradient F/x; find stretching work from the triangular area ½Fx. For 8 N at 0.04 m, W = 0.16 J.
- For a weight comparison, use W = mg with the local value of g. For example, a 3 kg object weighs 30 N where g = 10 N/kg; its mass remains 3 kg on another planet.
In plain language
Forces deform materials, and a spring's graph measures stiffness and stored energy. Gravity attracts masses; weight depends on local field strength.
Self-check
A spring extends 0.05 m under a 10 N force within its linear range. Find k and the work stored.
Show the answer
k = F/x = 10/0.05 = 200 N/m. Work is the triangle area ½Fx = 0.25 J.
- Higher
Scope: Higher · Examination tier: Higher Tier · §2c legacy P2.2/P2.3 support grouping; dagger-marked PM2.3v–vi are shared-tier outcomes taught in a separate shared requirement
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- This legacy support card is not a tier map or teaching destination. Plain-dagger PM2.3v–vi are shared-tier; use J249:shared-p2-pressure-and-moments for their equations, calculation methods and practice.
What to do in an assessment
- Use the shared-tier requirement J249:shared-p2-pressure-and-moments for pressure and moment equation selection, calculations and practice.
In plain language
This legacy card only points to the shared-tier destination and introduces no Higher-only pressure or moment equations.
Self-check
Are PM2.3v–vi Higher-only equations?
Show the answer
No. They are plain-dagger outcomes assessed in both Foundation and Higher, with their teaching in the shared-tier pressure-and-moments requirement.
- Higher
Scope: Higher · Examination tier: Higher Tier · §2c bold P2.1f, P2.2e–h, P2.2j–k and P2.2q; Appendix 5d bold Higher-only PM2.2ii
Open revision guidance
What to know
- P2.1f — The signed area under a velocity–time graph gives displacement; use areas of rectangles and triangles and retain the signs and units.
- P2.2e–f — Combine vectors to find a resultant and draw a free-body diagram showing every external force on one chosen object. Equilibrium means the vector sum of forces is zero.
- P2.2g–h — A non-zero resultant causes acceleration in its direction. In a falling object, drag increases with speed until it balances weight; terminal velocity is then constant because the resultant force is zero. A vehicle's speed changes when its driving, braking, drag and friction forces are unbalanced.
- P2.2j–k and PM2.2ii (bold Higher-only) — Inertial mass is the ratio of the resultant force on an object to the acceleration it produces (m = F/a); it measures resistance to acceleration. Momentum is p = mv and total momentum is conserved in an isolated system.
- P2.2q — At constant speed on a circular path, direction and velocity change continuously; centripetal acceleration and resultant force point toward the centre.
What to do in an assessment
- For terminal velocity, compare weight and drag through the fall; for a vehicle, identify all forces and their resultant before explaining acceleration or braking.
- Split a velocity–time graph into signed geometric areas and state whether the result is displacement or distance.
- For Higher-only PM2.2ii, calculate p = mv for each object and direction, then compare total momentum before and after an isolated interaction. Example: 2 kg at 3 m/s sticks to 1 kg at rest, so shared velocity = (2×3 + 1×0)/(2+1) = 2 m/s.
In plain language
Higher Tier adds force diagrams, terminal velocity, motion-graph areas, momentum and circular motion.
Self-check
A 2 kg cart moving at 3 m/s sticks to a stationary 1 kg cart. What is their shared velocity if external forces are negligible?
Show the answer
Initial momentum is 2×3 + 1×0 = 6 kg m/s. Total mass is 3 kg, so shared velocity is 6/3 = 2 m/s in the original direction; this uses Higher-only PM2.2ii.
- Core
Scope: Core · §2c shared-tier P2.2l, P2.3j–o and dagger-marked mathematical outcomes PM2.3v–vi
Open revision guidance
What to know
- P2.2l — For a fixed change in momentum, increasing the time taken reduces the average force; this explains why airbags and crumple zones reduce the force on vehicle occupants.
- P2.3j — Weight is gravitational force and depends on mass and local gravitational field strength; distinguish mass from weight.
- P2.3k–m — Forces can turn objects about a pivot. The turning effect depends on force and its perpendicular distance from the pivot; levers and gears can trade force for distance or speed.
- P2.3n–o — Pressure is force normal to a surface per unit area. Pressure differences in fluids can create resultant forces; a liquid transmits pressure through a confined volume.
- PM2.3v — Pressure p = F/A when force acts normal to a surface; calculate pressure in pascals from force in newtons and area in square metres.
- PM2.3vi — Moment = force × perpendicular distance from pivot to the force's line of action; use N m and the perpendicular distance.
What to do in an assessment
- Explain a safety feature by relating longer stopping time to a smaller average force. Describe a pivot and force line when comparing turning effects.
- For a 20 N normal force on 0.5 m², p = F/A = 40 Pa. For a 12 N force perpendicular to a lever 0.25 m from its pivot, moment = 3.0 N m.
In plain language
Momentum changes affect impact force; shared-tier pressure and moment equations quantify force normal to a surface and turning effects.
Self-check
Why does an airbag reduce injury risk in a collision?
Show the answer
It increases the time over which the occupant's momentum changes, reducing the average force.
Topic group
P3 Electricity
- Core
Scope: Core · §2c Topic P3, P3.1a–g and P3.2a–m
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- Static charge results from transfer of electrons; like charges repel and unlike charges attract. A current is a rate of flow of charge, and potential difference is energy transferred per unit charge.
- In a series circuit the current is the same at every point and component potential differences add; parallel branches share the supply potential difference while current divides between branches.
- Resistance links current and potential difference. Component behaviour can be investigated from current–potential-difference data; electrical power and energy transfer depend on current, potential difference and time.
What to do in an assessment
- Use conventional circuit symbols and place ammeters in series and voltmeters across the component being measured.
- State whether a relationship applies to a particular component before using it; do not assume every component has constant resistance.
In plain language
Track charge flow, potential difference and resistance separately, then use the circuit arrangement to predict how current and energy transfer are shared.
Self-check
Where should a voltmeter be connected to measure a lamp's potential difference?
Show the answer
In parallel across the lamp, so it measures the energy transferred per unit charge across that component.
- Core
Scope: Core · §2c P3.1a–c, P3.1e–g and P3.2a–m; mathematical outcomes PM3.1i and PM3.2i–iv
Open revision guidance
What to know
- P3.1a — Charge is a property of matter with positive and negative types. A neutral body has equal amounts of positive and negative charge; electrons carry negative charge.
- P3.1b–c — Rubbing can transfer electrons between materials, leaving one with excess electrons (negative) and the other with a deficit (positive). Charge can redistribute through conductors, while it remains localized on an insulator; charged bodies attract or repel without contact and a spark is a sudden discharge through air.
- P3.1d — An electric field is a region where a charged object experiences an electric force. Field direction is defined as the force direction on a positive test charge; a negative charge is forced oppositely.
- P3.1e and PM3.1i — Current is the rate of charge flow: Q = It. Charge flows around a complete conducting circuit only when there is a source of potential difference and a closed path.
- P3.1f — In a single closed series loop, current has the same value at every point; charge is not used up by a component.
- P3.2a — Series circuits have one path: current is common and potential differences share the supply. Parallel circuits have branches: each branch has the supply potential difference and current divides at junctions; measuring instruments must be connected correctly (ammeter in series, voltmeter in parallel).
- P3.2b — Draw d.c. circuit diagrams with standard symbols and polarity for cells/power supplies, switches, fixed/variable resistors, filament lamps, diodes, LDRs, NTC thermistors, ammeters and voltmeters.
- P3.2c–e — Current depends on potential difference and resistance; potential difference is energy transferred per unit charge. V is measured in volts, I in amperes and R in ohms. V = IR for an ohmic resistor at constant temperature, but a filament lamp heats as current rises, an NTC thermistor's resistance falls as it warms, and a diode conducts mainly in one direction.
- P3.2f — A circuit investigation changes one factor (usually p.d. or resistance) while measuring current and controlling component temperature where relevant; choose a series ammeter and parallel voltmeter.
- P3.2g–h — Plot I–V data to classify a component. A straight line through the origin means proportional response/constant resistance; a curved trace signals changing resistance. A filament lamp's resistance rises as it heats, a diode conducts mainly one way, an NTC thermistor's resistance falls as it warms, and an LDR's resistance falls as light intensity increases.
- P3.2f–h — A variable-resistance wire changes resistance by changing the active wire length: a longer length has greater resistance. To investigate this, set up a uniform resistance wire in series with a low-voltage supply and ammeter, with a voltmeter across the active length. Move a slider/contact to vary that length; record V and I at each length and calculate R = V/I. Keep wire material, cross-sectional area and temperature (including current/heating time) the same, use the same supply and meter ranges, repeat readings, and compare resistance with length. Distinguish this wire test from investigating a component's own characteristic.
- P3.2i — In series, resistances add because the same current passes through each and the required p.d.s add. In parallel, adding a branch provides another route for charge, reducing total resistance qualitatively.
- P3.2j — In series, calculate equivalent resistance Rₜ = R₁ + R₂ and use the same current through each; in parallel, use the same p.d. across branches and add branch currents.
- P3.2k — Use a circuit diagram to plan a measurement/test, select meter range and component ratings, open the switch while changing connections, then close it only to take readings.
- P3.2l and PM3.2iii — Electrical power P = VI (also P = I²R for a resistor); energy transferred depends on power and time. A device transfers more energy per second when its power is greater.
- P3.2m and PM3.2i–iv — Apply V = IR, E = QV, Q = It, P = VI, P = I²R and E = Pt. E can be in J using W and seconds or kW h using kW and hours; 1 kW h = 3.6 × 10⁶ J.
What to do in an assessment
- For a two-resistor series circuit with a 12 V supply and 2 Ω + 4 Ω, Rₜ = 6 Ω and I = 2 A; the p.d.s are 4 V and 8 V. Check that their sum is 12 V.
- For a parallel circuit, use the same branch p.d. and add branch currents. Show how each reading follows from the circuit topology before substituting into an equation.
- For a component characteristic, build from a diagram with a current-limiting resistor/variable resistor, measure I and V over a safe range, derive R = V/I (or use an ohmmeter with the circuit isolated), reverse a diode only with current limiting, plot the data and compare gradient/shape.
- For the P3.2f wire-length investigation, vary only the active length of the same uniform wire. Measure p.d. across that length and current through it, calculate R = V/I, and compare repeated values against length. Keep material and diameter fixed; use a small current, allow the wire to cool between readings, and keep temperature as constant as possible so heating does not confound the length effect.
- For energy billing, 1.5 kW used for 2 h transfers 3.0 kW h; convert to joules only if required, multiplying by 3.6 × 10⁶.
In plain language
Current measures charge flow, voltage measures energy per charge, and resistance describes opposition to current. Circuit layout determines how those quantities are shared.
Self-check
How would you test how resistance depends on the length of a resistance wire?
Show the answer
Vary only the active length of the same wire; measure current through it and p.d. across that length, calculate R = V/I, and compare repeated readings while controlling material, cross-section and temperature.
- Core
Scope: Core · §2c legacy supporting card formerly grouped with P3.1d; source leaf now mapped as shared-tier
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- P3.1d — An electric field is a region where a charged object experiences an electric force. The field model explains attraction/repulsion without contact: field direction is the force direction on a positive test charge, while a negative charge is forced in the opposite direction.
- A field can be represented by lines/arrows; closer lines indicate a stronger field. Opposite charges attract and like charges repel because their field interactions produce forces in those directions.
What to do in an assessment
- For a charged-object explanation, identify the sign of each charge, state whether the force is attractive or repulsive, and connect it to the field rather than implying contact.
- Use the field direction convention carefully: it is defined for a positive test charge, not the motion direction of an electron.
In plain language
An electric field is the invisible region in which charges exert forces; it explains static attraction and repulsion at a distance.
Self-check
In which direction is an electric field defined, and which way would an electron's force point?
Show the answer
Field direction is the force direction on a positive test charge. An electron is negative, so its force is opposite to the field direction.
- Core
Scope: Core · §2c P3.1d (shared-tier statement)
Open revision guidance
What to know
- P3.1d — An electric field is a region where a charged object experiences an electric force. Field direction is defined as the force direction on a positive test charge; a negative charge experiences force in the opposite direction.
- A charged insulator can retain charge locally because electrons cannot move freely through it; in a conductor, charge can redistribute. This distinction helps explain static charging and discharge.
What to do in an assessment
- Identify the charge sign before predicting force direction; do not use an electron's force direction to define the field.
In plain language
Electric fields explain attraction and repulsion between charged objects without contact.
Self-check
An electron is placed in an electric field. Which way is its force relative to the field?
Show the answer
Opposite to the field direction, which is defined for a positive test charge.
Topic group
P4 Magnetism and magnetic fields
- Core
Scope: Core · §2c Topic P4, P4.1a–g and P4.2a–j
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- A magnetic field describes the force a magnet or current can exert in the region around it; field lines indicate direction and relative strength.
- A current-carrying conductor in a magnetic field experiences a force. A motor uses this effect to transfer electrical energy to movement.
- Changing magnetic flux can induce a potential difference and current. Transformers use changing current in a primary coil and a shared iron core to change alternating potential difference.
What to do in an assessment
- Use field diagrams to show direction and identify where the field is strongest.
- When describing induction, state what changes in the magnetic field or conductor motion and connect that change to the induced output.
In plain language
Fields explain magnetic forces, motors turn electrical input into movement, and changing magnetic conditions can induce an electrical output.
Self-check
What must change for a potential difference to be induced in a coil?
Show the answer
The magnetic field linked to the coil must change, for example because a magnet or coil moves relative to the other.
- Core
Scope: Core · §2c shared-tier P4.1a–g
Open revision guidance
What to know
- P4.1a — Like poles repel and unlike poles attract. A permanent magnet retains its magnetism; an induced magnet becomes magnetic in an external field and usually loses most magnetism when that field is removed.
- P4.1b — Magnetic materials can be magnetised by an external field; distinguish a permanent magnet from a temporary/induced magnet by whether it retains magnetism after the inducing field is removed.
- P4.1c — Field lines show direction (north to south outside a magnet) and relative strength (closer spacing is stronger). The field is strongest near the poles and changes direction/strength across space.
- P4.1d — A compass needle aligns with the local magnetic field. Its directional behaviour around Earth is evidence that Earth has a magnetic field, consistent with magnetic material and moving charge in the core.
- P4.1e — A current in a wire produces a magnetic field around it. Show this by placing plotting compasses near a straight wire, briefly closing the circuit and observing needle deflection; reversing current reverses the field. Right-hand grip convention: thumb points with conventional current and curled fingers show the circular field direction.
- P4.1f — The field around a straight conductor becomes stronger as current increases and weaker with distance from the wire.
- P4.1g — A solenoid produces a stronger, more uniform field when its current or number of turns increases; a longer solenoid has a weaker field than a shorter one with the same number of turns and current because its turns are less concentrated. Inserting a soft-iron core strengthens the field.
- Shared P4.1 motor-effect context — A current-carrying conductor in a magnetic field can experience a force because the fields interact. Identify the current and field directions qualitatively; quantitative force calculation is Higher-only PM4.2i and is taught in J249:higher-p4-motor-effect.
What to do in an assessment
- Sketch field lines with arrows and sensible spacing; for a wire/solenoid, use the current direction to predict the field before checking with a compass.
- To investigate solenoid factors, place a small compass at a fixed position and orientation inside or at the end of the solenoid. Connect it to a low-voltage supply with an ammeter and variable resistor; vary one factor at a time (current, number of turns, or solenoid length), keeping the others fixed, and compare compass deflection as a measure of field strength. For the length test, compare solenoids with the same turns and current but different lengths; repeat readings, reverse polarity as a check, and switch off between changes to limit heating.
- To show the field around a wire, set a plotting compass at several positions near the conductor, close the switch only to observe deflection, then reverse current and compare. For the motor effect, identify field and conventional-current directions qualitatively; do not use the Higher-only magnitude equation here.
- Use Fleming's left-hand rule only with three mutually perpendicular directions and conventional current; reversing either current or field reverses force.
In plain language
Magnets and currents create fields; interacting fields exert forces. The motor effect uses those forces to turn an electrical input into motion.
Self-check
How can you investigate whether solenoid length affects field strength?
Show the answer
Keep current and number of turns fixed, compare different solenoid lengths using compass deflection at the same position and orientation, and repeat readings; a longer solenoid has the weaker field.
- Higher
Scope: Higher · Examination tier: Higher Tier · §2c bold Higher-only P4.2e–j; Appendix 5d bold Higher-only PM4.2ii
Open revision guidance
What to know
- P4.2e — A changing magnetic field linked to a conductor induces a potential difference; if the circuit is complete, it drives current. The induced current's magnetic field opposes the change that produced it (Lenz's law).
- P4.2f — An alternator uses relative motion/rotation to keep changing magnetic flux and generate alternating current; a dynamo produces direct current by making the output unidirectional.
- P4.2g — In a transformer, alternating current in the primary coil produces changing magnetic flux in a shared iron core, inducing an alternating p.d. and current in the secondary coil. A steady d.c. input does not continuously induce an output.
- P4.2h–i and PM4.2ii — For an ideal transformer, Vp/Vs = Np/Ns. More turns on the secondary give a larger p.d. (step-up); fewer turns give a smaller p.d. (step-down).
- P4.2j — In a dynamic microphone, sound pressure vibrates a diaphragm and attached coil relative to a magnet; changing flux induces a varying p.d./current. In a loudspeaker/headphone, varying current in a coil in a magnetic field creates force that vibrates a diaphragm and produces sound.
What to do in an assessment
- To increase induced output, increase the rate of magnetic-flux change (move faster, use a stronger magnet or more turns); state what changes and why an output is induced.
- For a transformer, label primary/secondary and turns before using Vp/Vs = Np/Ns. Example: 1000 primary turns and 100 secondary turns with 230 V input give Vs = 23 V.
- Compare microphone and speaker as reverse energy conversions: sound vibration to electrical signal by induction, then electrical signal to sound by motor effect.
In plain language
A changing magnetic field can make electricity. Transformers transfer alternating electrical energy between coils, and microphones/speakers convert between sound and electrical signals.
Self-check
A transformer has 800 turns on its primary and 200 on its secondary. If Vp = 240 V, what is Vs?
Show the answer
Vs = Vp × Ns/Np = 240 × 200/800 = 60 V, so it is step-down.
- Higher
Scope: Higher · Examination tier: Higher Tier · §2c bold P4.2a–d; Appendix 5d bold Higher-only PM4.2i
Open revision guidance
What to know
- P4.2a — A magnet and current-carrying conductor exert forces on one another because their magnetic fields interact.
- P4.2b — Fleming's left-hand rule relates field, conventional current and force in three perpendicular directions.
- P4.2c — Reversing current or magnetic field reverses the force direction.
- P4.2d — Opposite sides of a current loop experience opposite forces, producing a turning effect in a motor.
- Appendix 5d PM4.2i (bold Higher-only) — For a conductor at right angles to a magnetic field, calculate force with F = BIl, where B is magnetic flux density in teslas, I current in amperes and l the perpendicular length in metres.
What to do in an assessment
- Use first finger for field (N to S), second for conventional current and thumb for force; reverse one input to predict a reversed force.
- For Higher-only PM4.2i, convert B to teslas, I to amperes and perpendicular length l to metres before substituting. Example: 0.20 T × 3 A × 0.10 m gives F = 0.06 N.
In plain language
The motor effect is the force produced when a current interacts with a magnetic field.
Self-check
A 0.15 m conductor at right angles to a 0.40 T field carries 2 A. What force acts on it?
Show the answer
Higher-only PM4.2i: F = BIl = 0.40 × 2 × 0.15 = 0.12 N.
Topic group
P5 Waves in matter
- Core
Scope: Core · §2c Topic P5, P5.1a–k, P5.2a–j and P5.3a–e
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- Wave speed, frequency and wavelength are linked; transverse and longitudinal waves differ in the direction of oscillation relative to energy transfer.
- The electromagnetic spectrum is ordered by wavelength and frequency; all electromagnetic waves travel at the same speed in a vacuum but interact differently with matter.
- Reflection and refraction change wave direction; transmission, absorption and scattering depend on the material and wave. Sound and seismic waves provide evidence about materials that cannot be inspected directly.
What to do in an assessment
- Use a labelled wave diagram to identify amplitude, wavelength and direction of travel.
- Explain a change in wave behaviour by identifying the boundary or material interaction and the resulting change in direction, speed or energy.
In plain language
Describe a wave with measurable quantities, then explain what reflection, refraction, absorption or transmission does at a material boundary.
Self-check
What happens to frequency when a wave enters a different medium?
Show the answer
The frequency remains set by the source; if the wave speed changes, its wavelength changes accordingly.
- Core
Scope: Core · §2c P5.1a–e, P5.1j–k, P5.2a–h; mathematical outcome PM5.1i
Open revision guidance
What to know
- P5.1a–b — Amplitude is maximum displacement from equilibrium; wavelength λ is the distance between matching points on successive cycles; period T is time for one cycle; frequency f is cycles per second, with f = 1/T.
- P5.1c–d and PM5.1i — Wave speed v = fλ. Keep frequency in hertz, wavelength in metres and speed in m/s; if speed changes at a boundary while frequency stays fixed, wavelength changes.
- P5.1e — In a transverse wave, oscillation is perpendicular to energy transfer; in a longitudinal wave, oscillation is parallel and produces compressions/rarefactions.
- P5.1j–k — Water ripples model transverse waves while air sound is longitudinal. Measure wave speed from wavelength and frequency (or distance/time); the disturbance travels, but water or air particles oscillate about positions rather than travelling with the wave.
- P5.2a–b — Electromagnetic waves are transverse and transfer energy from a source to an absorber without requiring a material medium.
- P5.2c–d — The spectrum from long wavelength/low frequency to short wavelength/high frequency is radio, microwave, infrared, visible, ultraviolet, X-ray, gamma. Frequency and wavelength are inversely related for the same wave speed.
- P5.2e–f — Human eyes detect only a narrow visible range; visible light is electromagnetic radiation, not a separate kind of wave.
- P5.2g — Applications include radio communication, microwave heating/communications, infrared heaters/remote controls, visible vision/lighting, UV fluorescence/sterilisation, X-ray imaging and gamma medical treatment/sterilisation.
- P5.2h — UV, X-rays and gamma rays can damage tissue; X-rays and gamma are ionising and can damage DNA, while UV can damage skin/eyes. Risk depends on exposure/dose and is reduced by limiting exposure and appropriate shielding.
What to do in an assessment
- Measure wavelength between matching points, measure frequency by counting cycles in a known time, then calculate v = fλ. Example: 5 Hz × 0.40 m = 2.0 m/s.
- Use a slinky to distinguish parallel/perpendicular oscillation; use a ripple tank or sound trace to determine wavelength/period and identify which medium particles vibrate.
- For spectrum questions, compare wavelength/frequency order before naming a use or hazard; don't claim all EM waves need air or that visible light is the only EM radiation.
In plain language
Waves move energy, not the material as a whole. Their measurable properties link speed, wavelength and frequency; EM waves form one spectrum with different interactions and uses.
Self-check
A wave travels at 12 m/s with frequency 30 Hz. What is its wavelength?
Show the answer
λ = v/f = 12/30 = 0.40 m.
- Higher
Scope: Higher · Examination tier: Higher Tier · §2c legacy mixed P5.1/P5.2/P5.3 grouping; exact shared and Higher leaves are scoped separately
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- Legacy grouping only: exact source-leaf teaching and tier assignments are provided in the separately scoped requirements and source crosswalk.
What to do in an assessment
- At a medium change, keep f fixed and use v = fλ to calculate the new wavelength; label incident, reflected and transmitted rays separately.
- Draw a normal at the point of incidence, mark equal incident/reflected angles, and show refraction direction based on the relative wave speeds; no lens or refraction equation is required by these clauses.
- For medical imaging comparisons, state what interaction creates contrast, what signal reaches the detector, and one safety/limitation implication.
In plain language
This legacy mixed support card is not a tier or completion claim.
Self-check
How do you construct a ray diagram for reflection and refraction at a boundary?
Show the answer
Draw the boundary and normal, measure angles from the normal, make the reflection angle equal the incidence angle, and show the refracted ray bending towards the normal if it enters a slower medium.
- Core
Scope: Core · §2c P5.1f–g and P5.3c–e (shared-tier statements)
Open revision guidance
What to know
- P5.1f — At a boundary, frequency remains fixed by the source; if speed changes, wavelength changes according to v = fλ.
- P5.1g — A wave may be reflected, transmitted into the next medium or absorbed.
- P5.3c † — Separate-science content taught at both tiers: convex lenses converge parallel rays while concave lenses diverge them. Both refract light and can form images, but their different shapes produce opposite effects on parallel rays. Convex lenses can correct long-sightedness and concave lenses can correct short-sightedness.
- P5.3d † — Separate-science content taught at both tiers: construct two-dimensional ray diagrams for reflection, refraction and lenses. For a boundary, draw a normal at the point of incidence and label angles from it; reflected rays obey angle of incidence = angle of reflection. At a change of medium, a ray changes direction when its speed changes (towards the normal when it slows, away when it speeds up). For a lens, draw the principal axis and focal points: parallel rays converge through the principal focus after a convex lens and diverge as if from the focus after a concave lens. Show incident, reflected/refracted and emergent rays on the correct sides of each surface.
- P5.3e † — Separate-science content taught at both tiers: an object's colour depends on the visible wavelengths it reflects or transmits and absorbs. A smooth surface can produce specular reflection, sending rays in a definite direction; a rough surface scatters reflected light in many directions. White surfaces reflect or scatter most visible wavelengths, while a black surface absorbs most visible light.
What to do in an assessment
- Keep frequency fixed at a boundary and use relative wave speed to explain wavelength and ray-direction changes.
- For a ray construction, draw a normal first and measure each angle from it; distinguish a smooth mirror-like specular reflection from diffuse scattering at a rough surface.
In plain language
Boundaries change wave direction, speed or energy; lenses and selective absorption explain familiar optical effects.
Self-check
How do you construct a ray diagram for reflection and refraction at a boundary?
Show the answer
Draw the boundary and normal, measure angles from the normal, make the reflection angle equal the incidence angle, and show the refracted ray bending towards the normal if it enters a slower medium.
- Higher
Scope: Higher · Examination tier: Higher Tier · §2c bold P5.1h–i, P5.2i–j and P5.3a–b
Open revision guidance
What to know
- P5.1h–i — Sound vibrates the eardrum; ossicles transmit vibration to the cochlea, where it becomes nerve signals. Vibrating solids can create sound in air; hearing spans a limited frequency range that commonly narrows with age.
- P5.2i — Ultrasound, X-rays, infrared and gamma radiation form images through differences in reflection, transmission and absorption by materials.
- P5.2j — Oscillating charges can generate radio waves, and incoming radio waves can induce oscillations in a receiving circuit.
- P5.3a–b — Materials can absorb, transmit, reflect or refract electromagnetic waves differently at different wavelengths.
What to do in an assessment
- For imaging, identify the wave interaction that creates contrast and what signal reaches the detector.
In plain language
Higher Tier applies wave behaviour to hearing, medical imaging and radio communication.
Self-check
How can an ultrasound image show a boundary between tissues?
Show the answer
Part of the wave reflects where tissue properties change, and the returned signal indicates the boundary.
Topic group
P6 Radioactivity
- Core
Scope: Core · §2c Topic P6, P6.1a–l and P6.2a–e
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- Atoms have a nucleus of protons and neutrons with electrons around it; isotopes have the same proton number but different neutron numbers.
- Unstable nuclei emit alpha, beta or gamma radiation. Their different charge, mass and penetrating power explain how they behave in fields and materials.
- Radioactive decay is random for an individual nucleus but predictable for a large sample. Half-life describes the time for the number of undecayed nuclei or activity to halve.
What to do in an assessment
- Balance nuclear equations by conserving nucleon number and proton number.
- Compare hazards and uses by distinguishing ionisation, penetration, exposure time, distance and shielding.
In plain language
Nuclear structure explains the kinds of radiation; decay is random for one nucleus but follows a measurable pattern across a large sample.
Self-check
A radioactive sample has a half-life of 6 hours. What fraction remains after 18 hours?
Show the answer
Three half-lives have passed, so one eighth of the original undecayed nuclei remain.
- Core
Scope: Core · §2c P6.1a–j, P6.1l and P6.2a
Open revision guidance
What to know
- P6.1a — A nucleus contains protons and neutrons. Proton number sets the element and its positive nuclear charge; neutron number changes the mass without changing the element.
- P6.1b — Isotopes are atoms of the same element (same proton number) with different neutron numbers and therefore different nucleon/mass numbers.
- P6.1c — Write a nuclide as ᴬ_ZX: A is nucleon number, Z is proton number, and neutron number is A−Z. Use the symbol to identify charge and composition.
- P6.1d–e — Some nuclei are unstable and emit alpha particles (two protons and two neutrons), beta particles (electrons), neutrons or gamma photons. Alpha reduces A by 4 and Z by 2; beta-minus leaves A unchanged and raises Z by 1; gamma changes neither; neutron emission lowers A by 1 and leaves Z unchanged.
- P6.1f–g — Nuclear equations must conserve total nucleon number and total proton number on both sides. Use common nuclide/particle symbols and balance A and Z independently.
- P6.1h — Electrons occupy energy levels around the nucleus. An atom can absorb radiation and excite an electron to a higher level; when it falls, it emits radiation. Losing outer electrons makes a positive ion.
- P6.1i — Changes in electron energy levels and nuclear states can emit or absorb electromagnetic radiation over a wide frequency range; gamma rays are high-frequency, high-energy nuclear radiation.
- P6.1j — Radioactive decay is random for any one nucleus. Half-life is the time for the number of undecayed nuclei or activity in a sample to halve; it describes a large sample statistically.
- P6.1l — Alpha is strongly ionising and weakly penetrating (stopped by paper/skin); beta is moderately penetrating (stopped by thin metal); gamma is weakly ionising and highly penetrating (attenuated by thick lead/concrete).
- P6.2a — Irradiation is exposure to radiation from outside; contamination is radioactive material on/in an object. Contamination can continue to irradiate internally or externally until removed/decayed, so it is often more persistent and difficult to control.
What to do in an assessment
- Balance each nuclear equation twice: compare top numbers A and bottom numbers Z, then identify the missing particle/nucleus. Example: ²³⁸₉₂U → ²³⁴₉₀Th + ⁴₂He.
- For 80 g or 800 counts/min with half-life 3 h, after 9 h three half-lives leave 1/8: 10 g or 100 counts/min. Distinguish measured activity from undecayed nuclei.
- Compare hazards by source location, ionising ability, penetration, exposure time, distance and shielding; distinguish external irradiation from material deposited in the body.
In plain language
The proton/neutron make-up identifies a nucleus; unstable nuclei decay randomly but predictably in large samples, producing radiation with different penetration and hazards.
Self-check
How many neutrons are in ²³⁵₉₂U, and what fraction of a sample remains after four half-lives?
Show the answer
Neutrons = 235−92 = 143. The remaining fraction is (1/2)⁴ = 1/16.
- Core
Scope: Core · §2c legacy P6.2b–e grouping; these source statements are shared-tier
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- Legacy grouping only: P6.2b–e are shared-tier statements and their source-leaf teaching is mapped to the scoped common requirement.
What to do in an assessment
- Use the separately scoped shared nuclear-process requirement for the teaching content.
In plain language
This legacy shared-scope support card is not a tier or completion claim.
Self-check
What is the difference between a radioactive tracer and radiotherapy?
Show the answer
A tracer is detected from outside the body to follow an organ's function; radiotherapy uses ionising radiation to control or destroy unwanted tissue while limiting damage to healthy tissue. These † outcomes apply to both tiers.
- Core
Scope: Core · §2c P6.2b–e (shared-tier statements)
Open revision guidance
What to know
- P6.2b † — Separate-science content taught at both tiers: assess radiation hazard using source activity, exposure, distance, shielding, radiation type and half-life; half-life alone does not determine risk. For the same number of undecayed nuclei and radiation type, a shorter half-life generally means greater activity and a quicker fall in activity, so a source becomes less radioactive sooner; a longer-lived contaminant can remain hazardous for much longer. Consider the source, exposure and biological context rather than treating half-life as a risk score by itself.
- P6.2c † — Separate-science content taught at both tiers: radioactive tracers emit radiation that can be detected outside the body to follow an organ's function or locate a problem; a tracer should emit detectable radiation and have a suitably short half-life. Radiotherapy instead uses ionising radiation to control or destroy unwanted tissue such as cancer cells; treatment is targeted to limit damage to healthy tissue.
- P6.2d † — Separate-science content taught at both tiers: in nuclear fission a heavy nucleus usually first absorbs a neutron, becomes unstable and splits into smaller nuclei, releasing further neutrons. The products have slightly less total mass; the mass defect is converted to energy using ΔE = Δmc². Released neutrons can sustain a chain reaction.
- P6.2e — Fusion joins light nuclei and can release energy when the products have less mass than the reactants; high temperature and pressure are needed to overcome electrostatic repulsion.
What to do in an assessment
- Compare fission and fusion by starting nuclei, products, conditions and the origin of released energy.
In plain language
Nuclear processes can release energy when product mass is lower, and ionising radiation has both risks and useful applications.
Self-check
What is the difference between a radioactive tracer and radiotherapy?
Show the answer
A tracer is detected from outside the body to follow an organ's function; radiotherapy uses ionising radiation to control or destroy unwanted tissue while limiting damage to healthy tissue. These † outcomes apply to both tiers.
- Higher
Scope: Higher · Examination tier: Higher Tier · §2c bold P6.1k
Open revision guidance
What to know
- P6.1k — After n half-lives, the remaining fraction is (1/2)ⁿ; the activity or number of undecayed nuclei halves repeatedly.
What to do in an assessment
- Count the number of half-life intervals, then multiply the original quantity by (1/2)ⁿ.
In plain language
Repeated half-lives reduce the remaining amount by a factor of two each interval.
Self-check
What fraction remains after four half-lives?
Show the answer
(1/2)⁴ = 1/16.
Topic group
P7 Energy
- Core
Scope: Core · §2c Topic P7, P7.1a–e and P7.2a–g
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- Work is done when a force transfers energy through a distance in its direction; power is the rate of energy transfer or work done.
- Efficiency compares useful output with total input, using consistent energy or power quantities. Energy is conserved but can be dissipated to less useful stores.
- A system diagram can track energy stores and transfers before and after an event; it does not imply that energy disappears.
What to do in an assessment
- Choose the equation that matches the quantities and units given, then check whether the question asks for energy, work, power or efficiency.
- Identify where energy is transferred usefully and where it is dissipated when evaluating a device.
In plain language
Energy is conserved as it moves between stores; work and power describe transfer, while efficiency measures the useful fraction.
Self-check
A device takes in 500 J and transfers 350 J usefully. What is its efficiency?
Show the answer
350 ÷ 500 = 0.70, so its efficiency is 70%.
- Core
Scope: Core · §2c P7.1a–e, P7.2a–d and P7.2f–g; mathematical outcome PM7.2i and Appendix 5d energy equations
Open revision guidance
What to know
- P7.1a — In a closed system, total energy does not change. Energy is transferred between stores or to the surroundings; it is not created, destroyed or literally used up.
- P7.1b — Track stores through an event: a raised object gains gravitational potential energy; a moving body has kinetic energy; a slowing vehicle transfers kinetic energy to thermal stores in brakes/road/air; an obstacle collision redistributes energy as deformation, sound and heating.
- P7.1c — Heating changes internal energy/temperature; a force doing work transfers energy mechanically; current transfers energy electrically to components. These are distinct pathways into/out of system stores.
- P7.1d — Put mechanical, electrical and thermal transfers on a common joule scale. Use W = Fd, E = Pt, ΔE = mcΔθ and electrical energy relations; 1 kW h = 3.6 × 10⁶ J.
- P7.1e — Kinetic energy is Eₖ = ½mv², elastic energy in a linear spring is Eₑ = ½kx², and gravitational potential energy near Earth is Eₚ = mgh.
- P7.2a — Dissipation spreads energy into less useful stores, usually heating the surroundings. Total energy remains conserved even when the energy is difficult to recover.
- P7.2b — Domestic devices transfer energy from batteries or the a.c. mains into useful outputs and unwanted heating/sound; trace input, intended output and waste pathway for each device.
- P7.2c — Appliance power rating is the rate of energy transfer. A 2 kW heater transfers energy faster than a 1 kW heater under the same conditions; E = Pt links rating and use time.
- P7.2d and PM7.2i — Efficiency = useful energy output ÷ total energy input (or useful power ÷ total power) × 100%. The useful fraction cannot exceed 100%.
- P7.2f — Improve efficiency by reducing unwanted transfer: lubricate moving parts to reduce friction, insulate hot systems, seal draughts and choose components that direct more input to the useful output.
- P7.2g — A thicker wall or a wall of lower thermal conductivity reduces the rate of heat transfer and slows cooling; the relationship is qualitative.
What to do in an assessment
- Draw a before/after store-and-pathway diagram, include the surroundings for dissipation, then calculate the useful fraction. If 800 J input gives 280 J useful, efficiency = 35%.
- A 1.5 kW appliance running for 2 h uses 3.0 kW h = 10.8 MJ. Match kW with hours or W with seconds.
- Select an energy equation by the physical store/process; for example, 2 kg raised 3 m at g = 10 N/kg gains 60 J of GPE.
In plain language
Energy is always conserved, but some spreads into stores that are hard to use. Power tells how quickly transfer happens; efficiency measures the useful share.
Self-check
A device receives 500 J and delivers 125 J usefully. What is its efficiency, and where has the rest gone?
Show the answer
Efficiency = 125/500 × 100% = 25%. The remaining 375 J has been transferred to less useful stores such as heating or sound, not destroyed.
- Higher
Scope: Higher · Examination tier: Higher Tier · §2c bold P7.2e
Open revision guidance
What to know
- P7.2e — Explain how reducing unwanted energy transfers, for example by insulation or reducing friction, increases the fraction transferred usefully.
What to do in an assessment
- Name the unwanted pathway and explain how the proposed change reduces it.
In plain language
An efficiency improvement reduces wasted transfer so a larger share of input becomes useful output.
Self-check
How does insulating a hot-water tank improve efficiency?
Show the answer
It reduces unwanted thermal transfer to the surroundings, so more input energy remains useful.
Topic group
P8 Global challenges
- Core
Scope: Core · §2c Topic P8, P8.1a–i, P8.2a–j and P8.3a–i
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- Physics models transport systems through forces, energy transfer, motion and efficiency; compare designs using measurable performance and the constraints in the question.
- Electricity generation and the national grid involve energy resources, changing supply and demand, and transmission at high potential difference to reduce energy lost in cables.
- Astronomy uses observations, spectra and models to infer properties and histories of celestial bodies. The Sun is a star; gravity and radiation link objects in the Solar System and beyond.
What to do in an assessment
- When evaluating an energy resource or transport system, separate evidence about output, reliability, environmental effect and cost.
- Distinguish direct observation from a conclusion inferred through a model or measurement.
In plain language
Use physics models to compare transport and energy choices, and use observations plus evidence-based models to explain astronomical systems.
Self-check
Why are transmission voltages raised for electricity sent over long distances?
Show the answer
For a given power transfer, higher voltage allows a lower current, reducing resistive heating losses in transmission cables.
- Core
Scope: Core · §2c P8.1a–e and P8.1g
Open revision guidance
What to know
- P8.1a — Everyday speeds range from walking (about 1–2 m/s), running (a few m/s), cycling (several m/s) and cars on roads (tens of m/s) to sound in air (about 340 m/s) and wind (variable, often a few to tens of m/s). These are estimates, not fixed limits.
- P8.1b — Everyday accelerations can be estimated from change in velocity divided by time; small human accelerations are around 1 m/s², while road vehicles can accelerate or brake by several m/s².
- P8.1c — Convert units consistently before calculating rates: km/h ÷ 3.6 gives m/s; acceleration is change in m/s divided by seconds.
- P8.1d — Human reaction time can be measured with a ruler-drop test: catch distance is converted to fall time using free-fall motion, or use a stimulus and timer. A typical response is a few tenths of a second and varies with attention/fatigue.
- P8.1e — Stopping distance = thinking distance + braking distance. Thinking distance increases with speed and reaction time; braking distance increases with speed and depends on braking force, tyres, road grip, weather, vehicle condition and mass/load.
- P8.1g — Large deceleration means a large force (F = ma) and can injure occupants or damage vehicles. Seat belts, airbags, crumple zones and barriers increase stopping time/distance and reduce peak force.
What to do in an assessment
- Use the ruler-drop data consistently: measure from the release point to the catch point, repeat, convert to time using a free-fall relation if provided, and compare conditions fairly.
- Explain a safety change through the relevant factor: wet/icy road lowers grip; distraction or tiredness raises reaction time; worn brakes increase braking distance.
- For stopping-distance questions, separate thinking from braking and state which factors change each part instead of treating total distance as one cause.
In plain language
A vehicle keeps travelling while a driver reacts and then while brakes slow it. Speed, reaction and road conditions all affect how far it takes to stop.
Self-check
Why does doubling speed more than double braking distance in a simplified constant-braking-force model?
Show the answer
Kinetic energy is proportional to speed squared. The brakes must remove four times as much kinetic energy at double speed, so braking distance rises by more than a factor of two.
- Core
Scope: Core · §2c P8.2a–e and P8.2g–j; mathematical outcome PM8.2i
Open revision guidance
What to know
- P8.2a — Earth uses non-renewable fossil fuels and nuclear fuels, and renewable sources such as wind, solar, hydroelectric, tidal, wave, geothermal and biofuel. To compare how they generate electricity: fossil fuels and biofuels are burned to heat water and make steam that turns a turbine and generator; nuclear fission heats water for the same steam–turbine–generator pathway. Wind turns a turbine directly; falling or flowing water turns hydroelectric turbines, and tidal barrages/streams use moving seawater to drive turbines. Wave devices use wave motion to drive a generator, directly or through a turbine. Solar photovoltaic cells convert light directly into electrical energy, while solar-thermal systems concentrate sunlight to heat a fluid and drive a turbine. Geothermal heat can provide steam or hot water to drive a turbine. Compare how they are replenished, reliability, output, environmental effects and storage needs.
- P8.2b — Energy-resource use changes over time as technology, costs, demand, policy and environmental evidence change; distinguish a trend in data from an unsupported prediction.
- P8.2c–d — The National Grid sends electricity at high p.d. from power stations and steps voltage down locally for domestic use. Step-up/step-down transformers change p.d. during transfer.
- P8.2e — For fixed power P = VI, raising voltage lowers current. Since cable heating loss is I²R, high-voltage transmission reduces energy lost in cables and makes the grid efficient.
- P8.2g — UK domestic supply is alternating current at about 230 V and 50 Hz.
- P8.2h — Direct voltage maintains one polarity/current direction; alternating voltage repeatedly reverses polarity, so current changes direction periodically.
- P8.2i — The live wire is about 230 V relative to neutral/earth; neutral is near 0 V and completes the normal circuit; earth is a safety conductor, normally carrying no current, that provides a low-resistance path if a fault makes a casing live.
- P8.2j — Opening a switch may leave the live wire on the supply side at dangerous potential. A live-to-earth connection can drive a large current through a person or fault path; insulation, earth connection and fuse/breaker reduce risk.
- PM8.2i — For an ideal transformer, input electrical power VpIp equals output VsIs; real transformers lose some energy as heating/sound, so output power is less.
What to do in an assessment
- Compare energy sources using a stated criterion and evidence; separate renewable status from reliability or environmental impact.
- Use P = VI to explain grid transmission: for a fixed transmitted power, increased V reduces I and therefore resistive loss. Do not claim transformers create energy.
- On a domestic wiring diagram, identify live, neutral and earth by function and potential; state why earth is connected to exposed conductive cases and why a switch must interrupt the live conductor.
In plain language
The grid changes voltage to move power with less cable heating, then supplies homes with alternating electricity. Wiring roles and earthing protect users.
Self-check
Why is electricity transmitted at high voltage rather than at the domestic 230 V?
Show the answer
For the same power, high voltage means lower current; cable heating losses are proportional to I²R, so lower current reduces energy wasted.
- Higher
Scope: Higher · Examination tier: Higher Tier · §2c legacy mixed P8.1/P8.3 grouping; exact shared and Higher clauses are mapped separately
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- Legacy mixed grouping only: exact P8 source-leaf teaching and tier assignments are in the separately scoped shared and Higher requirements.
What to do in an assessment
- Consult the scoped shared and Higher requirements for the current teaching content.
In plain language
This legacy grouped support card is not a tier or completion claim.
Self-check
What does the red shift of light from distant galaxies show?
Show the answer
Receding galaxies have light shifted to longer wavelengths; more distant galaxies generally recede faster, evidence that the Universe is expanding. Together with CMBR, this supports the Big Bang model.
- Core
Scope: Core · §2c P8.1f, P8.1i and P8.3a–e (shared-tier statements)
Open revision guidance
What to know
- P8.1f and P8.1i — Use order-of-magnitude estimates for thinking/braking distances and vehicle force or acceleration; check that the estimated values and units are sensible.
- P8.3a–b † — Separate-science content taught at both tiers: light from a galaxy receding from us is red-shifted because its observed wavelength is longer (and frequency lower) than when emitted. More distant galaxies generally recede faster; this speed–distance trend is evidence that the Universe is expanding. Red shift together with other evidence, including the cosmic microwave background radiation (CMBR), supports the Big Bang model.
- P8.3c † — Separate-science content taught at both tiers: the Sun formed when gravity drew together a cloud of gas and dust. Compression raised the core temperature until fusion began; energy released by fusion produces an outward effect that balances the inward gravitational collapse. A star's later life cycle depends on its mass.
- P8.3d — Stars and other bodies emit radiation; hotter bodies emit more intensely and peak at shorter wavelengths.
- P8.3e † — Separate-science content taught at both tiers: the eight planets, outward from the Sun, are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. The inner four are rocky and the outer four are giant planets; they differ in size, composition and distance but all orbit the Sun. The Solar System also contains minor planets, natural moons and artificial satellites. Moons orbit planets; artificial satellites are made and launched for purposes such as communication, navigation, observation or research. Geostationary satellites orbit above the equator with a period matching Earth's rotation and appear fixed over one location, making them useful for communications and continuous weather observation. Polar satellites pass over or near both poles as Earth rotates beneath them, making them useful for mapping and observing different parts of Earth. Natural satellites form naturally and usually orbit planets; artificial satellites are human-made, while both orbit a larger body and can be used to observe or investigate it.
What to do in an assessment
- Use a scale estimate before calculation; in astronomy distinguish the observation from the model-based conclusion drawn from it.
In plain language
Shared-tier content uses estimates for transport and observations to describe the Solar System, stars and cosmic expansion.
Self-check
What does the red shift of light from distant galaxies show?
Show the answer
Receding galaxies have light shifted to longer wavelengths; more distant galaxies generally recede faster, evidence that the Universe is expanding. Together with CMBR, this supports the Big Bang model.
- Higher
Scope: Higher · Examination tier: Higher Tier · §2c bold P8.1h, P8.2f and P8.3f–i
Open revision guidance
What to know
- P8.1h — Estimate road forces from F = ma using plausible vehicle mass and acceleration, with sensible units and significant figures.
- P8.2f † (Higher-only, bold) — Separate-science content, assessed only in Higher Tier: a transformer's potential-difference ratio follows its turns ratio, Vp/Vs = Np/Ns. In an ideal transformer, input power equals output power (VpIp = VsIs); therefore a step-up transformer raises potential difference and lowers current for the same transferred power. This is why high-voltage transmission reduces current and resistive cable losses (I²R); the turns ratio sets the voltage change, not an increase in energy.
- P8.3f–g † (Higher-only, bold) — Separate-science content, assessed only in Higher Tier: gravity supplies the centripetal force for a circular orbit. A planet's velocity changes continuously because its direction changes, even when its speed stays constant. For a stable circular orbit around the same body, changing orbital speed requires a change in orbital radius: a greater speed requires a smaller radius, while a lower speed requires a larger radius.
- P8.3h † (Higher-only, bold) — Separate-science content, assessed only in Higher Tier: a body's temperature depends on the balance between absorbed incoming radiation and emitted radiation. If it absorbs more than it emits it warms; if it emits more than it absorbs it cools, until a new balance is reached. Everyday examples include a drink cooling in a room and a surface warming in sunlight. Earth's temperature depends on incoming solar radiation, reflection by clouds/ice/surface (albedo), absorption by land, oceans and atmosphere, and outgoing infrared radiation. The atmosphere lets much of the incoming solar radiation through but absorbs and re-emits some outgoing infrared radiation, affecting the balance.
- P8.3i † (Higher-only, bold) — Separate-science content, assessed only in Higher Tier: seismic P-waves can travel through solids and liquids, whereas S-waves travel through solids but not liquids. Comparing their velocities, absorption and reflection at boundaries lets scientists infer hidden structures; the absence of S-waves through the liquid outer core is evidence for that liquid layer. The same principle is used in deep-water SONAR: transmitted and reflected sound waves, with their travel time and behaviour in water and at boundaries, reveal the depth or position of an object that cannot be seen directly. Wave transmission, speed, absorption and reflection differ between solids and liquids.
What to do in an assessment
- For each inference, identify observation, physical mechanism and conclusion; for transformer calculations, write primary/secondary turns before substituting.
In plain language
Higher Tier adds quantitative force estimates and more detailed physical explanations of transformers, orbits, climate balance and Earth's interior.
Self-check
A step-up transformer has twice as many secondary turns as primary turns. For the same transferred power, what happens to secondary voltage/current, and why is that useful for transmission?
Show the answer
Vs/Vp = Ns/Np = 2, so secondary voltage doubles and ideal secondary current halves. Lower current reduces I²R cable heating losses; the transformer transfers power rather than creating it.
Topic group
P9 Practical skills
- Core
Open revision guidance
What to know
- J249 Topic P9 groups required work into PAGs: Materials, Forces, Motion, Measuring waves, Energy, Circuit components, Series and parallel circuits, and Interactions of waves.
- Learners need practice measuring length, area, mass, time, volume and temperature; determining density; measuring force, extension, speed, acceleration, energy, current, potential difference and resistance; constructing circuits; and observing wave interactions.
- PAG P1 Materials specifically requires accurate measurement and recording of length, area, mass, time, volume and temperature, then using measurements to determine the densities of solid and liquid objects. For a regular solid, measure its mass and dimensions; for an irregular solid, use displacement/overflow; for a liquid, find the mass of a known volume.
- PAG P2 Forces — use suitable apparatus to measure force and extension. Clamp a spring beside a vertical ruler, record its unloaded length, add known masses in small steps, convert added mass to force using W = mg, read length at eye level, calculate extension from the starting length and plot force against extension. Repeat readings and stop before permanent deformation.
- PAG P3 Motion — use a trolley on a ramp with a measured track distance and stopwatch, light gates or motion sensor. Release without a push, measure speed from distance/time or gate intervals, collect speeds at multiple times/positions to calculate acceleration or plot velocity against time, and repeat while controlling ramp angle and trolley/load.
- PAG P4 Measuring waves — use a ripple tank with a vibrating dipper and ruler/strobe to view wavefronts; measure several wavelengths across multiple crests, count cycles for frequency, then determine wave speed from v = fλ. Select apparatus suited to waves in fluids/solids and justify whether it resolves wavelength, frequency or speed.
- PAG P5 Energy — determine a metal's specific heat capacity using a balance, immersion heater, thermometer/temperature probe, power supply and joulemeter (or VIt measurement). Measure mass and initial temperature, insulate the block, heat for a timed interval, record energy input and final temperature, then calculate c = E/(mΔT). Secure electrical leads and handle hot metal with protection.
- PAG P6 Circuit components — investigate I–V characteristics with a d.c. supply, ammeter in series, voltmeter in parallel and variable resistor/current limit. Change p.d. gradually, record paired current/p.d. values for a resistor, filament lamp, diode or thermistor, reverse a diode only with current limiting, and plot I against V.
- PAG P7 Series and parallel circuits — use circuit diagrams to construct and check series and parallel circuits with cells/supply, switch, lamps and other common elements. Open the switch before changing wiring; place ammeters in series and voltmeters across components; compare bulb brightness/current/p.d. using the same supply and component ratings.
- PAG P8 Interactions of waves — observe reflection/refraction in fluids and solids and electromagnetic-wave interactions with matter. Use a ray box, plane mirror, glass block or prism, paper, ruler and protractor to trace incident/reflected/refracted rays and measure angles from the normal; use an appropriate detector/absorber to observe transmission, reflection or absorption safely.
- PAGs collectively include accurate length, area, mass, time, volume and temperature measurement, appropriate apparatus selection, safe energy/current work, and observation of the effects of waves on matter. Centres can substitute another activity only if it covers the required apparatus and techniques.
- The centre's separate obligation to offer at least eight practical activities is not evidence that this guide performed them or a learner competency/guide-completion gate. The methods here prepare for practical-skills questions in written papers.
- Written practical-skills questions across Paper 1 and Paper 2 assess method choice, variables and controls, apparatus suitability, tables/graphs, calculations, resolution/uncertainty, anomalies, conclusions, evaluation/improvements and risk reduction; practicals are not coursework.
- Appendix 5h — The employer is responsible for health and safety and must assess hazardous procedures before they are carried out. Local model risk assessments must be checked/adapted to conditions, significant controls recorded in point-of-use instructions, and guidance sought before unfamiliar or novel procedures; never proceed when risk controls are inadequate.
What to do in an assessment
- Identify independent, dependent and control variables; select suitable apparatus and a measurement range before collecting repeated readings.
- For PAG P1, tare a balance or subtract the empty-container mass; read liquid menisci at eye level; measure regular dimensions more than once; or collect displaced water without trapping air, then calculate density with consistent units.
- For PAG P2, record unloaded and loaded spring lengths separately; subtract to find extension, not total length. Use multiple force-extension readings and describe the proportional/elastic region from the graph.
- For PAG P3, use a consistent start/release point, keep ramp angle fixed, repeat runs and calculate mean values. If timing manually, time several intervals or use gates/video to reduce reaction-time error.
- For PAG P4, average wavelengths across several wavefront spacings; use a measured frequency and identify uncertainty in locating a crest or timing cycles.
- For PAG P5, minimise heat loss with insulation, use a known electrical energy input, measure the temperature rise of the metal rather than the heater, and repeat while avoiding burns and electrical hazards.
- For PAG P6/P7, draw and check the circuit before connecting the supply; choose meter ranges, avoid short circuits and excessive current, take repeated paired readings, and compare the measured graph/circuit quantities with predictions.
- For PAG P8, mark the ray path before moving apparatus, draw a normal at each surface, measure angles from the normal, and compare what is reflected, transmitted, refracted or absorbed; do not look into intense sources.
- Record units and instrument resolution, use an appropriate table or graph, identify anomalies, calculate from data, and evaluate precision, uncertainty and safety.
In plain language
Prepare for written questions by practising the apparatus, measurements, data handling and safe methods required across all eight J249 practical groups.
Self-check
Does completing the practical activities replace a written practical-skills examination?
Show the answer
No. Practical skills are assessed in written papers, and the activities prepare learners to answer questions about methods, apparatus and data.
Topic group
Appendix skills
- Core
Scope: Core · Appendices 5d Equations in Physics, 5e Units in science, 5f Working scientifically and 5g Mathematical skills requirements
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- Working scientifically spans models and explanations, planning and carrying out investigations, analysis and evaluation, and evidence-informed conclusions; the topic tables link individual outcomes to these skills.
- Physics calculations require equation selection, rearrangement, substitution with units, appropriate significant figures and checking whether an answer is physically plausible.
- Graphs require labelled axes and units, suitable scales, plotted data and a justified line or curve; gradient and area are interpreted only in the context of the relationship being tested.
What to do in an assessment
- Show the relationship used, substitute values with units, convert to a consistent unit system, and report a rounded answer with a unit where required.
- Support a conclusion with measured evidence and identify a limitation or improvement linked to the method.
In plain language
Use evidence and mathematical models carefully: plan fair measurements, show working, use units, interpret graphs and evaluate how reliable a conclusion is.
Self-check
Why should a graph's axes include units?
Show the answer
Units identify the measured quantities and scales, so the data and any gradient or relationship can be interpreted correctly.
Topic group
P1 Pressure
- Higher
Scope: Higher · Examination tier: Higher Tier · §2c legacy mixed P1.3 grouping; scoped shared and Higher source leaves are mapped separately
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- P1.3c — Gas pressure acts perpendicular to a surface. Pressure over an area produces a normal force; pressure differences across a surface can produce a net force. Gases compress or expand when pressure changes.
- P1.3d — For a fixed mass of gas at constant temperature, pressure falls as volume rises because wall collisions become less frequent. The plain-dagger PM1.3i equation is taught in the shared-tier requirement J249:shared-p1.3-gas-and-fluids.
- P1.3e — Work done compressing a gas transfers energy to its internal energy and raises temperature; a bicycle pump warms when its air is compressed.
- P1.3f — Model the atmosphere as a uniform-density fluid; atmospheric pressure at a point is due to the weight of air above it per unit area. The specification does not require named atmospheric layers.
- P1.3g — Atmospheric pressure decreases with height because less air lies above the surface, so the overlying column weighs less.
- P1.3h — Floating and sinking depend on weight, upthrust, displaced-fluid volume and the relative densities of object and fluid. An object rises when upthrust exceeds weight, sinks when weight exceeds the available upthrust, and floats at equilibrium when the two forces balance.
- P1.3i — Liquid pressure increases with depth and with liquid density. Pressure is greater below a partly submerged object than above it, creating an upward resultant force called upthrust.
- P1.3j and PM1.3ii — A liquid column gives Δp = ρgΔh between two depths. Use vertical depth difference, liquid density and g ≈ 10 N/kg near Earth's surface; the answer is in Pa (N/m²).
What to do in an assessment
- For a 2.0 m depth difference in water, Δp = 1000 × 10 × 2.0 = 20 000 Pa. Keep the density, depth and gravitational-field-strength units consistent.
- Explain floating with a force comparison and sketch arrows; explain atmospheric pressure by the overlying column; explain gas expansion by collision frequency rather than a change in particle size.
In plain language
This legacy support card is not the source-tier classification or teaching destination for the P1.3 leaves.
Self-check
Where is the plain-dagger gas pressure-volume calculation taught?
Show the answer
In the shared-tier requirement J249:shared-p1.3-gas-and-fluids, for Foundation and Higher.
- Higher
Scope: Higher · Examination tier: Higher Tier · §2c bold P1.3e, P1.3h–j and Higher-only mathematical outcome PM1.3ii
Open revision guidance
What to know
- P1.3e — Work done compressing a gas transfers energy to its internal energy and raises its temperature.
- P1.3h — An object floats when upthrust balances its weight; it sinks when weight exceeds upthrust and rises when upthrust is greater. The outcome depends on object and fluid density and displaced volume.
- P1.3i — Liquid pressure increases with depth and density. The pressure difference across an immersed object can create an upward resultant force called upthrust.
- P1.3j and PM1.3ii — For a liquid column, Δp = ρgΔh; pressure difference depends on liquid density, gravitational field strength and vertical depth difference.
What to do in an assessment
- Use Δp = ρgΔh with consistent SI units.
In plain language
Higher Tier adds gas compression, the force balance for floating, and quantitative liquid-column pressure.
Self-check
What does the liquid-column equation Δp = ρgΔh calculate?
Show the answer
It gives the pressure difference between two depths from liquid density, gravitational field strength and vertical depth difference.
Topic group
Working Scientifically and mathematics
- Core
Scope: Core · Appendix 5e SI base and derived quantities, symbols and units
Open revision guidance
What to know
- Base quantities: length d/h/l/s/x/λ in metres (m); mass m in kilograms (kg); time t in seconds (s); thermodynamic temperature T in kelvin (K); current I in amperes (A); amount of substance n in moles (mol).
- Area A is in square metres (m²); volume V is in cubic metres (m³), litres (L) or cubic decimetres (dm³); density ρ is in kg/m³.
- Celsius temperature θ is in degrees Celsius (°C), and change in Celsius temperature Δθ is also in °C; distinguish this from thermodynamic temperature T in K.
- Pressure p is in pascals (Pa); specific heat capacity c is in J/(kg °C); specific latent heat ℓ is in J/kg.
- Speed/velocity v/u is in m/s; force F or weight W in newtons (N); gravitational field strength g in N/kg; acceleration a in m/s²; frequency f in hertz (Hz).
- Energy E, change in thermal energy ΔE and work W are in joules (J); power P is in watts (W); electrical charge Q is in coulombs (C); potential difference V is in volts (V); resistance R is in ohms (Ω).
- Magnetic flux density B is in teslas (T); moment M is in newton metres (N m); momentum p is in kg m/s; period T is in seconds (s); spring constant k is in N/m.
- Transformer turns Np and Ns and efficiency are dimensionless. Energy may also be expressed in kW h when power is in kW and time in hours; 1 kW h = 3.6 × 10⁶ J.
What to do in an assessment
- Write a unit beside every measured/calculated quantity; convert before substituting if units do not match (for example, cm to m, g to kg, minutes to seconds).
- Check dimensions: density = mass/volume, speed = distance/time, force = mass × acceleration, and energy = power × time; a final unit should match the requested quantity.
- Use the quantity meaning to distinguish symbols that recur: m can denote mass or metre, V can be volume or volt, W can mean weight or work, p can mean pressure or momentum, and T can mean kelvin temperature or period.
In plain language
A correct numerical answer needs a unit that identifies the physical quantity. Symbols may repeat, so use context and dimensional checks.
Self-check
What is the SI unit for spring constant and for momentum?
Show the answer
Spring constant is N/m; momentum is kg m/s.
- Core
Scope: Core · Appendix 5f WS1.1a–i, WS1.2a–e, WS1.3a–i, WS1.4a–f and WS2a–d
Open revision guidance
What to know
- WS1.1a — Scientific methods and theories change when new technology gathers evidence and explanations are revised to fit it.
- WS1.1b — Use representational, spatial, descriptive, computational and mathematical models to predict, explain and solve familiar or unfamiliar physics problems; identify model assumptions.
- WS1.1c — Explain how science improves understanding/quality of life and acknowledge questions it cannot currently answer.
- WS1.1d — Discuss ethical questions raised by scientific developments using benefits, harms, consent, fairness and affected groups.
- WS1.1e — Explain everyday and technological applications of physics using the underlying principle.
- WS1.1f — Evaluate personal, social, economic and environmental consequences of an application, not only its technical performance.
- WS1.1g — Make a decision by weighing evidence, arguments, uncertainty and values; state why evidence supports the choice.
- WS1.1h — Evaluate practical and societal risks using likelihood, evidence and consequences; distinguish perceived risk from measured data.
- WS1.1i — Peer review tests methods and reasoning; communicate results clearly to different audiences and allow scrutiny/replication.
- WS1.2a — Use a physical model or theory to form a testable hypothesis that predicts how the dependent variable changes with the independent variable.
- WS1.2b — Plan a procedure to observe, measure, test a hypothesis or explore a phenomenon, including variables, range, repeats, controls and recording method.
- WS1.2c — Select appropriate instruments, apparatus, techniques and materials for the quantity/range required; justify resolution and safety.
- WS1.2d — Use representative sampling where a whole population cannot be measured; select samples without bias and state limits on representativeness.
- WS1.2e — Evaluate method limitations, propose a specific improvement and a follow-up investigation that tests a related question.
- WS1.3a — Present observations in a suitable descriptive, tabular, diagrammatic or graphical form with headings, scales and units.
- WS1.3b — Translate the same data between a table, graph, diagram, equation or written statement without changing its meaning.
- WS1.3c — Calculate and present appropriate statistics, including arithmetic mean, mode and median, and show the calculation/units where relevant.
- WS1.3d — Represent the distribution/range of results and estimate uncertainty; use repeats, resolution or spread to justify the estimate.
- WS1.3e — Interpret verbal, diagrammatic, graphical, symbolic and numerical evidence; identify patterns/trends, make inferences and draw conclusions.
- WS1.3f — Give a reasoned explanation that relates the data to the hypothesis/model and distinguishes evidence from assumption.
- WS1.3g — Evaluate objectivity, accuracy, precision, repeatability and reproducibility; repeated readings by one method are not the same as replication by another.
- WS1.3h — Identify random variation and systematic bias separately; explain how each affects results and how a method could reduce it.
- WS1.3i — Communicate the rationale, method, findings and conclusions with a logical scientific argument using diagrams, graphs, numbers and symbols.
- WS1.4a — Use scientific vocabulary, terminology and definitions accurately rather than relying on everyday meanings.
- WS1.4b — Recognise relevant physical quantities and explain how each is measured or determined.
- WS1.4c — Use SI base/derived units and accepted nomenclature unless inappropriate; refer to Appendix 5e for the listed quantities.
- WS1.4d — Use powers of ten and prefixes tera, giga, mega, kilo, deci, centi, milli, micro and nano correctly.
- WS1.4e — Convert units by applying the appropriate scale factor before calculation and preserve dimensions.
- WS1.4f — Give a sensible number of significant figures, consistent with data precision and the question.
- WS2a — Carry out an experiment following written instructions, manipulating apparatus correctly, measuring accurately and observing health-and-safety controls.
- WS2b — Make and record observations/measurements with a range of apparatus and methods, preserving raw data and units.
- WS2c — Present practical observations in descriptive, tabular, diagrammatic or graphical form.
- WS2d — Communicate the investigation rationale, method, findings and reasoned conclusions in paper-based or electronic verbal, diagrammatic, graphical, numerical and symbolic forms.
What to do in an assessment
- Before an investigation, state a testable hypothesis, identify independent/dependent/control variables, choose a suitable range and instrument, include repeats, define a safe procedure and plan how data will be presented.
- After collecting data, preserve raw observations, calculate suitable summaries, plot labelled axes, assess spread/uncertainty and error, relate the trend to the hypothesis, then evaluate limitations and propose a targeted improvement.
- For an evaluation or decision, separate evidence from opinion, state uncertainty and risk, consider affected groups and consequences, and communicate the conclusion so it can be checked.
In plain language
Working scientifically means making a fair, safe test, keeping reliable records, analysing evidence critically and explaining what the evidence can and cannot show.
Self-check
What is the difference between repeatability and reproducibility?
Show the answer
Repeatability is agreement when the same person repeats measurements with the same method/apparatus; reproducibility is agreement when conditions such as operator, equipment or method change.
- Core
Scope: Core · Appendix 5g physics mathematical skills M1a–d, M2a–c/f–h, M3a–d, M4a–f and M5a–c
Open revision guidance
What to know
- M1a — Recognise/use decimal notation and place value; convert correctly between decimal and ordinary units.
- M1b — Read and calculate with standard form A × 10ⁿ, including very small atomic or very large astronomical quantities.
- M1c — Use ratios, fractions and percentages for efficiency, probability-like comparisons and proportional relationships.
- M1d — Estimate a calculation's magnitude before evaluating it and use the estimate to detect implausible answers.
- M2h — Calculate orders of magnitude by comparing powers of ten.
- M2a — Use an appropriate number of significant figures in measured and calculated values.
- M2b — Find an arithmetic mean from repeated measurements; keep units and do not average unlike quantities.
- M2c — Construct/interpret frequency tables, diagrams, bar charts and histograms where the data type requires them.
- M2f — Distinguish and calculate mean, mode and median; use the statistic suited to the data and anomalies.
- M2g — Use a scatter diagram to identify positive/negative/no correlation, while recognising correlation alone does not prove causation.
- M3a — Interpret =, <, ≪, ≫, >, ≠ and ≈ correctly in inequalities, scales and scientific statements.
- M3b — Rearrange a formula to make a specified variable the subject, preserving equality.
- M3c — Substitute numbers with appropriate physical units into algebraic equations and track units through the calculation.
- M3d — Solve simple algebraic equations, including those with squares, ratios or a variable in a denominator when required.
- M4a — Translate information between a graph and numerical/table form.
- M4b — Interpret y = mx + c: m is gradient and c is the y-intercept; connect a linear graph to a physical relationship.
- M4c — Plot two variables from practical/other data using labelled axes, units, a sensible scale and suitable best fit.
- M4d — Determine gradient and intercept from a suitable best-fit line using well-separated points; include units on the gradient.
- M4e — Draw/use the slope of a tangent to a curve to estimate the instantaneous rate of change.
- M4f — Interpret and estimate the area between a curve and x-axis by counting squares or dividing into standard shapes; attach the correct physical units.
- M5a — Use and interpret angular measures in degrees, including angles of incidence/reflection and turns.
- M5b — Visualise and represent 2D/3D forms, including two-dimensional representations of 3D objects and physical systems.
- M5c — Calculate triangle/rectangle areas and cube surface areas/volumes for practical measurements and graph areas.
What to do in an assessment
- Write the equation, rearrange first if needed, convert to consistent units, substitute values, calculate, attach a unit and compare the result with an estimate.
- For a graph, label both axes with quantity/unit, choose a scale that uses the grid, plot accurately, draw an appropriate best-fit line, then select the correct gradient, tangent or area method for the physical question.
- For repeated data, retain raw values, calculate the requested mean/median and report precision that the instrument supports.
In plain language
Physics maths is about choosing a useful calculation or graph method, keeping units consistent and checking that the answer is plausible.
Self-check
A straight-line graph has y = 4x + 2. What are its gradient and y-intercept?
Show the answer
Gradient m = 4 and y-intercept c = 2, with units determined by the graph axes.
Topic group
Higher-tier supplement
- Higher
Scope: Higher · Examination tier: Higher Tier · §2c Topic P1–P8, bold statements identified by the specification as Higher Tier only
This explanation covers part of the source requirement only. Its tick is separate and does not count as a fully revised requirement.
Open revision guidance
What to know
- J249 distinguishes tier using bold topic-table statements: bold text is Higher-only, while unbolded topic statements are shared by Foundation and Higher.
- The dagger (†) identifies content found only in the Physics separate-science qualification; it is not a Higher-tier marker. Tier is determined independently by bold type.
- Higher candidates study the shared course plus source-bold additions; the affected Higher outcomes and equations have separately scoped teaching requirements.
What to do in an assessment
- Use the separately scoped Higher requirements and source crosswalk to distinguish Higher-only additions from shared outcomes.
- Do not infer tier status from a calculation's apparent difficulty or from a broad topic title.
In plain language
Higher Tier includes the shared course plus the exact source-bold additions, which are mapped separately from shared statements.
Self-check
Does every item in a Higher-tier topic become Higher-only?
Show the answer
No. Only the statements marked bold are Higher-only; the other statements are assessed in both tiers.
Topic group
Assessment guidance
- Core
Open revision guidance
What to know
- Choose one tier and sit both papers for that tier: Foundation candidates take J249/01 and J249/02; Higher candidates take J249/03 and J249/04. Paper 1 or 3 assesses P1–P4 and P9. Paper 2 or 4 assesses P5–P8, assuming knowledge of P1–P4 and P9. Each paper is 90 marks, 105 minutes and 50% of the qualification; the qualification is linear and externally assessed.
- Each paper has 15 marks of multiple-choice questions and 75 marks of short-answer practical, mathematical and structured questions. Every paper also has a six-mark Level of Response extended-response question. Papers 2 and 4 contain synoptic assessment, connecting ideas from more than one physics area and potentially combining application, practical planning or analysis and evaluation of data.
- The qualification assessment objectives are AO1 knowledge and understanding (40%), AO2 application (40%) and AO3 analysis, evaluation and experimental judgement (20%). For each paper these are 20%, 20% and 10% of the qualification respectively.
- Foundation assesses grades 1–5; Higher assesses grades 4–9, with grade 3 available on Higher for a candidate just below the grade 4 boundary. Only source-bold statements are Higher-only; unbolded statements are shared across tiers. The dagger (†) indicates separate-science scope, not tier.
- Read command words in the context of the whole question. Calculate obtains a numerical answer with workings shown. Determine and find obtain a value or solution using procedures or calculations; find is more commonly used for Foundation Tier. Estimate assigns an approximate value. Show supplies the steps, details or calculations that prove an answer; include working and units where appropriate.
- Describe sets out facts or characteristics; for a process, state what happens and when or where. Explain gives reasons or a mechanism. Analyse separates information into components and identifies their characteristics; it can also require discussing pros and cons and making a reasoned comment. Compare and contrast identify similarities and differences. Discuss addresses a range of ideas or arguments; evaluate makes a judgement using relevant evidence; conclude reaches a reasoned decision; justify gives a reasoned case.
- Choose selects from alternatives; select chooses what best suits the purpose; classify assigns a category. Identify recognises, lists, names or characterises; name gives the appropriate term. Define states a term's meaning; state or define expresses the nature, state or meaning precisely.
- Complete adds missing words, numbers, labels or plots. Construct writes or draws the requested item; convert changes one defined form to another. Deduce works out an answer using knowledge or data; recall retrieves a specification fact; suggest offers a possible idea or method.
- Design plans and presents the requested function, object, system or process, including its layout or workings as appropriate; plan sets out what is to be done. Draw produces a sufficiently detailed labelled diagram; sketch gives a simple freehand illustration, or the shape of a graph without precise plotted points. Label adds identifying words or symbols; illustrate clarifies with examples or diagrams.
- Measure establishes a value using an instrument or technique. Plot puts data into a labelled graph or chart; predict judges a future event using knowledge or evidence. Outline gives the main characteristics; use or using means base the answer on the supplied information.
- Give asks for a short answer unless an explanation is requested. How asks in what way; what requests information clarified by the context; which asks you to identify the object, word or explanation; why asks for a reason; write asks you to present the required information.
- For an asterisked Level of Response answer, develop a sustained, coherent, relevant, substantiated and logically structured line of reasoning. For a synoptic question, connect the relevant principles rather than treating each topic in isolation.
- The assessment is in English. There is one series each year in May/June and all examined papers must be taken in the same series. Unlimited retakes are permitted, but a retake must include all papers for the relevant tier. Add the two paper marks for the total weighted mark, then use the grade boundaries for the candidate's tier, entry option and examination series.
What to do in an assessment
- Before revising a paper, identify the entered tier, paper code and topic scope; remember that Paper 2/4 assumes the earlier P1–P4 and P9 knowledge.
- Use the command word to decide what evidence or reasoning to provide. Show calculation steps and units, support judgements with evidence, and structure six-mark responses as a connected explanation rather than an unlinked list.
- When a question is synoptic, identify which ideas from different topics apply and show how they connect to the context, method or data.
In plain language
The qualification has two papers at one chosen tier. Know their scopes and weighting, use command words to shape answers, connect topics in synoptic questions, and build a clear evidence-based extended response.
Self-check
A candidate enters Higher Tier, earns 62 marks on Paper 3 and 70 on Paper 4, and answers a six-mark asterisked question. Which papers did they sit, how much of the qualification is Paper 4, and what should the extended response do?
Show the answer
They sit J249/03 and J249/04. Paper 4 is 50% of the qualification. The extended response should develop a sustained, coherent, relevant, substantiated and logically structured line of reasoning; the two paper marks are added and compared with the applicable Higher-tier grade boundaries for that series.
Verified qualification
OCR GCSE: Physics B (Twenty First Century Science) (J259)
Exam years · 2027Specification version · Version 5.0 (July 2026)
Course details
OCR · GCSE PhysicsJ259Exam years · 2027
Assessment For assessment details, see the official specification.
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Reviewed course guidance
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Examination tier
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Topic group
P1 Radiation and waves
- Core
Scope: Core · §2c Chapter P1–P8 / Appendix 5d–5h; exact source-leaf scope recorded in inventory.sourceLeafCrosswalk
Open revision guidance
What to know
- P1.1.1–5 — The electromagnetic spectrum, longest to shortest wavelength, is radio, microwave, infrared, visible (red to violet), ultraviolet, X-ray, gamma. Frequency and photon energy increase in that order. All EM waves travel at about 3.0 × 10⁸ m/s in vacuum; a material may change their speed. Eyes detect only visible light. Radiation transfers energy from source to absorber; materials transmit, reflect or absorb it depending on wavelength and material.
- P1.1.6 — In an atom, electrons occupy different distances/energy levels around the nucleus. Absorbing or emitting electromagnetic radiation can change electron arrangement; losing outer electrons forms a positive ion.
- P1.1.7a–e — Nuclear changes emit gamma rays. Changes in atomic electrons emit X-rays, ultraviolet and visible light. High-energy UV, X-rays and gamma can ionise some atoms by removing electrons. UV absorbed by oxygen forms ozone; ozone absorbs UV and helps protect life. Molecules emit and absorb infrared.
- P1.1.8–9 — UV, X-rays and gamma can harm tissue; ionisation can damage or kill cells and increase cancer risk. Applications reflect interactions: radio communications, microwaves cooking/communications, infrared heating/thermal imaging, visible vision/lighting, UV sterilisation, X-ray imaging, gamma sterilisation or cancer treatment. Weigh benefits against dose, exposure, shielding and who bears risk; do not confuse hazard (capacity to harm) with risk (likelihood and severity in a situation).
- P1.1.10 [Higher Tier only] — Oscillating current in a transmitting circuit produces radio waves. An incoming radio wave makes electrons oscillate in a conductor; the induced oscillating current is detected by a receiver circuit.
What to do in an assessment
- Order the seven bands and describe trends in wavelength/frequency/energy without reversing the order.
- For a radiation application, state the wave, interaction, benefit, hazard, and a proportionate control; support a technology decision with evidence.
- Worked example: a transmitter oscillates at 100 MHz. This is a radio wave; its receiver detects it because the field drives an alternating current in its aerial, which its electronics process.
In plain language
The spectrum is one family of energy-carrying waves. How waves are generated and interact with matter explains both useful technologies and radiation hazards.
Self-check
How does a radio receiver detect a radio wave, and why is X-ray exposure controlled?
Show the answer
The wave induces an oscillating current in a receiving conductor. X-rays can ionise atoms and damage tissue, so exposure is limited by time, distance and shielding.
- Core
Scope: Core · §2c Chapter P1–P8 / Appendix 5d–5h; exact source-leaf scope recorded in inventory.sourceLeafCrosswalk
Open revision guidance
What to know
- P1.2.1 — Every body emits EM radiation. As temperature rises, emission intensity rises and the distribution shifts towards shorter wavelengths/higher principal frequency. Temperature affects both amount and spectrum.
- P1.2.2 [Higher Tier only] — A body’s temperature changes according to the balance between incoming radiation absorbed and radiation emitted. At equilibrium absorbed/incoming energy balances emitted/outgoing energy. Everyday example: a mug cools when it emits more energy than it absorbs; it warms under a lamp when it absorbs more than it emits. Earth absorbs solar radiation and emits mainly infrared; atmospheric greenhouse gases (including water vapour, carbon dioxide and methane) absorb and re-emit some outgoing IR in all directions, reducing net escape and warming the surface. Earth’s temperature depends on incoming solar intensity, reflectivity/albedo, atmospheric composition/greenhouse effect, and the balance achieved between absorption and emission.
- Human activities, especially fossil-fuel burning and forest loss, have raised atmospheric CO₂; methane and other greenhouse gases also matter. Climate models combine physical principles with evidence, make predictions, and are refined as new observations arrive.
- P1.2 evidence — Assess long-run measurements (temperature, gas concentrations and other climate indicators) rather than single weather events. Correlation alone does not prove cause: consider mechanism, other factors, data quality and model assumptions. A model is strengthened, not proven, when diverse evidence and predictions agree.
What to do in an assessment
- Read graphs with axes, units, timespan, trend and uncertainty; separate weather from climate and correlation from causal explanation.
- Worked example: if Earth absorbs 240 W/m² on average but emits 230 W/m², it gains 10 W/m²; temperature tends to rise until outgoing emission balances absorption (other conditions held constant).
- State both evidence and limitation when judging a climate claim; a hot or cold day is not decisive evidence about a long-term global trend.
In plain language
Climate reasoning links radiation balance to temperature and tests explanations against long-term evidence, not isolated events.
Self-check
A planet absorbs more radiation than it emits. What happens to its temperature, and what condition indicates equilibrium?
Show the answer
Its energy store and temperature tend to rise; equilibrium occurs when absorbed/incoming energy balances emitted/outgoing energy.
- Core
Scope: Core · §2c Chapter P1–P8 / Appendix 5d–5h; exact source-leaf scope recorded in inventory.sourceLeafCrosswalk
Open revision guidance
What to know
- P1.3.1–5 — A wave is a regular disturbance transferring energy in its direction of travel without net transfer of matter. Amplitude is maximum displacement; wavelength λ is distance between corresponding points on adjacent waves; frequency f is cycles per second (Hz); period T is seconds per cycle, T=1/f. Transverse oscillations are perpendicular to travel (rope); longitudinal oscillations are parallel and create compressions/rarefactions (sound in air). Water ripples and sound demonstrate that the wave travels while medium particles oscillate about positions.
- P1.3.6 — Apply v=fλ (m/s=Hz×m) to water, sound and EM waves. Example: f=5 Hz and λ=0.40 m gives v=2.0 m/s. Rearrange as f=v/λ or λ=v/f and show unit consistency.
- P1.3.7a — Measure water-ripple speed by timing many crests passing a fixed point (frequency = number/time) or tracking a crest over measured distance/time. Measure sound speed over a long known baseline by timing a sound event at a distance, or use echoes with round-trip distance 2d and time t (v=2d/t); repeat and average. Control distance and timing uncertainty.
- P1.3.7b — Ripple tank: use a dipper and strobe/scale. Frequency is source cycles per second (or count crests passing a point per second). Measure the distance across several adjacent crests and divide by number of wavelengths to obtain λ. Determine speed with v=fλ or by crest displacement/time. Keep water depth constant; repeat and average.
- P1.3.8a–c — At interfaces waves may reflect, refract (change direction when speed changes), or transmit. Prism method: direct a narrow ray at a glass prism, mark incident/emergent paths, remove prism, draw boundaries/normals, measure angles; repeat and trace the refracted path and dispersion. Plane mirror method: draw mirror line and normal, direct a narrow ray, mark incident/reflected rays with pins, remove mirror, draw rays, measure angles from normal; repeat at different incidence angles. Use i=r.
- P1.3.9–10 [Higher Tier only] — Wave speed differs between media and can vary with wavelength. Refraction follows a speed change: frequency remains source-set, so wavelength changes (v=fλ); oblique entry changes direction, normal entry changes speed/wavelength without bending. P1.3.11–12 [shared Foundation/Higher] — Light is an electromagnetic wave; electromagnetic waves are transverse. Outcomes 9–10 are Higher Tier only; outcomes 11–12 are shared.
- P1.4.1–2 [separate Physics qualification] — Draw specular-reflection rays with normal and arrows; angles are measured from normal and i=r. Scattering from a rough surface sends rays in many directions. At a plane boundary draw incident, reflected and refracted rays. A prism refracts different wavelengths by different amounts and separates white light into a spectrum (red longest visible wavelength, violet shortest). These ray diagrams are qualitative only.
- P1.4.3–5 — Convex lenses converge parallel rays toward a focal point; concave lenses diverge rays as if from a focal point. Compare ray paths qualitatively, not lens equations. At an interface waves may transmit or be absorbed. Colour results from wavelength-dependent absorption, transmission and scattering: a filter transmits selected colour(s) and absorbs much else; an object’s apparent colour is the light it scatters/transmits to the eye. White reflects/scatters all visible colours; black absorbs nearly all incident visible light.
- P1.4.6–7 [Higher Tier only; separate Physics qualification] — Sound is transmitted through solids (and liquids) as vibrations; e.g. a string telephone, a knock conducted through a table, or bones conducting sound to the inner ear. Middle-ear bones transmit especially efficiently around 1–3 kHz, a limited range relevant to human hearing; the audible range is broader but hearing sensitivity varies with frequency.
- P1.4.8 [Higher Tier only; separate Physics qualification] — Ultrasound is reflected at tissue boundaries; echo time and strength locate structures. Earthquake waves travel and reflect/refract at geological boundaries, revealing hidden layers. SONAR sends a sound pulse and detects its echo from an underwater object; range = speed × round-trip time / 2. P1.4.9 [shared Foundation/Higher; separate Physics qualification] — Across media, frequency remains constant at a boundary while speed and wavelength change together: v=fλ. A higher speed at fixed f means longer wavelength.
What to do in an assessment
- Use labelled diagrams to distinguish transverse/longitudinal motion, incident ray, normal, angles, reflected/refracted ray and wave direction.
- Practical: repeat timings/angle readings, use several wavelengths or a long baseline, maintain controls, average, and discuss uncertainty.
- Worked echo: a SONAR echo returns in 0.40 s; sound speed in water is 1500 m/s. Range = 1500×0.40/2 = 300 m.
- Worked refraction: f=4 Hz and speed changes from 2 to 3 m/s. λ changes from 0.50 to 0.75 m; frequency stays 4 Hz.
In plain language
Measure waves by timing cycles and spacing crests; reflection, refraction and material interactions explain light, sound and sensing.
Self-check
A wave enters a slower medium at an angle. What stays constant, and what happens to wavelength and direction?
Show the answer
Frequency stays constant. Wavelength decreases because v=fλ; at oblique incidence the wave bends because one part changes speed first.
Topic group
P2 Sustainable energy
- Core
Scope: Core · §2c Chapter P1–P8 / Appendix 5d–5h; exact source-leaf scope recorded in inventory.sourceLeafCrosswalk
Open revision guidance
What to know
- P2.1.1–3 — Chemical stores in batteries/fuels transfer energy electrically: current does work on a heater, motor or other domestic device. Power is energy transferred per second; appliance energy depends on rating and use time. E=Pt: use J=W×s or kWh=kW×h. Example: 2.0 kW for 3 h uses 6.0 kWh = 21.6 MJ.
- P2.1.4–6 — In a closed system total energy is conserved even when useful energy becomes dissipated into less useful thermal stores/surroundings (and sometimes sound). Reduce unwanted transfer using insulation, lubrication, streamlining or low-resistance connections as relevant.
- P2.1.7 — Building cooling is faster through thinner, more thermally conductive walls; thicker/low-conductivity insulation reduces transfer. Fair test: same area/material finish and starting temperature, vary thickness or conductivity, measure temperature change against time.
- P2.1.8 — Efficiency = useful energy transferred / total energy transferred (or ×100% for percentage). Example: 180 J useful from 600 J input gives 0.30=30%. [Higher Tier only clause] Describe ways to increase efficiency, such as reducing unwanted transfers or recovering waste energy.
- P2.1.9 — Sankey diagram: arrow width represents energy amount; input splits into useful and dissipated output, with widths proportional to values. Total output widths equal input width (conservation); efficiency is useful branch/input. Label units and system boundary.
- P2.2.1–3 — Resources: fossil fuels (coal, oil, gas), nuclear fuel, biofuel, wind, hydroelectricity, tides and the Sun/solar. Renewable resources are replenished on human timescales; non-renewables are finite or replenished too slowly. Fossil/biofuel/nuclear often heat water to steam, drive turbine and generator; wind/water/tides turn turbines directly; solar cells convert light directly to electrical energy. Compare availability/intermittency, controllability, power output, emissions, land/ecosystem effects, waste, construction/decommissioning, cost and geographic suitability. No resource is best against every criterion.
- P2.2.4–5 — UK domestic mains is alternating current/voltage (a.c.), about 230 V at 50 Hz; d.c. has fixed polarity/direction, whereas a.c. reverses direction periodically. National Grid transformers step voltage up for transmission and down for distribution/domestic use; at the same power, higher voltage means lower current and less cable heating loss.
- P2.2.6 — Live wire is at alternating potential (about ±325 V peak relative to neutral for a 230 V RMS supply); neutral is near 0 V and completes circuit; earth is a safety connection, normally near 0 V and carries current if a fault makes a case live so fuse/breaker disconnects. The live wire can remain dangerous when a switch is open if switching only neutral. Connecting live to an earthed object creates a large fault current, shock/fire risk; never defeat earth or touch mains conductors.
- P2.2.7 — Explain domestic/workplace/national energy-use patterns from data: appliance ownership, power and duration, population, industry, climate, efficiency, price and access can change demand and resource mix. Distinguish measured trend from explanation and compare contexts.
What to do in an assessment
- Cost: energy in kWh × tariff in £/kWh. For 1.5 kW × 2 h = 3 kWh; at £0.30/kWh cost = £0.90.
- For source comparisons name criteria, cite data, identify whose benefits/risks and state a qualified recommendation.
- For a Sankey, total input equals all output; proportional widths must match the numbers. Explain where dissipated energy goes.
In plain language
Energy is conserved but not all transfers are useful. Quantifying use, efficiency, generation and safety makes energy choices comparable.
Self-check
A device takes 500 J and delivers 125 J usefully. Find efficiency. Why does the National Grid transmit at high voltage?
Show the answer
Efficiency=125/500=0.25=25%. High voltage permits lower current for the same power, reducing resistive heating losses in cables.
Topic group
P3 Electric circuits
- Core
Scope: Core · §2c Chapter P1–P8 / Appendix 5d–5h; exact source-leaf scope recorded in inventory.sourceLeafCrosswalk
Open revision guidance
What to know
- P3.1.1–3 [separate Physics qualification] — Rubbing different surfaces transfers electrons; the object gaining electrons becomes negative and the one losing electrons positive. Charged objects exert non-contact forces: like charges repel, unlike attract; sparks are sudden discharges through air when charge separation creates a strong enough field. An electric field is the region around charge where another charge experiences force; field direction is the force direction on a positive test charge.
- P3.2.1 — Current is charge flow per second; charge flows only in a closed conducting loop with a source of potential difference. In a single closed series loop current has the same value at every point; charge is not used up.
- P3.2.2 — Q=It. Example: 0.40 A for 30 s transfers Q=12 C. Rearrange I=Q/t or t=Q/I and use C, A, s.
- P3.2.3–4a — Current depends on potential difference and resistance. V=IR; example 6.0 V across 12 Ω gives 0.50 A. For series components, total resistance is the sum, current is common, and supply voltage is divided; use V=IR per component and check voltage drops sum to supply.
- P3.2.4b — Wire-resistance practical: connect a test wire, ammeter and low-voltage d.c. supply in series; voltmeter parallel across measured length. Vary length or wire type while controlling material, diameter and temperature; record V and I, calculate R=V/I; repeat. Switch off between readings to limit heating. Circuit drawing uses standard symbols and meters in correct positions.
- P3.2.5–7 — A fixed resistor is approximately constant R; filament resistance rises as it heats; diode conducts mainly in one direction; LDR resistance decreases as light intensity rises; NTC thermistor resistance decreases as temperature rises. Plot I against V or V against I consistently: linear resistor has a straight proportional response at constant temperature; lamp curves as filament warms; diode blocks reverse direction; LDR/thermistor responses vary with illumination/temperature. Investigate with series ammeter, component, variable resistor and supply, with voltmeter across component; reverse diode polarity as needed and use safe ranges. Recognise circuit symbols for cell/battery, wires, switch, lamp, diode, LDR, thermistor, fixed/variable resistor, ammeter and voltmeter; show positive (+) and negative (−) terminals at the supply and preserve polarity when drawing/constructing the circuit.
- P3.3.1 — Potential difference is work/energy transferred per unit charge: V=W/Q. 1 V means 1 J transferred per coulomb.
- P3.3.2–4 — Series: same current everywhere; voltage drops add to supply; increasing one resistance raises equivalent resistance and changes current/voltage division. Parallel: each branch has supply p.d.; total current is sum of branch currents; adding a branch reduces equivalent resistance. For resistors in series Rtotal=R1+R2. Example 3 Ω and 5 Ω across 16 V: Rtotal=8 Ω; I=2 A; drops are 6 V and 10 V. Parallel equivalent resistance is qualitatively smaller than either branch resistor.
- P3.3.2b — Bulb brightness test: compare identical lamps in one series loop and in separate parallel branches across the same supply; keep supply and lamp type fixed, use circuit symbols and observe brightness. Add/remove a lamp and record effects; use safe low voltage.
- P3.3.5 — Use a d.c. series circuit, potential divider or sensor circuit to test components: filament heating, diode direction, LDR illumination response, NTC temperature response. A potential divider gives a variable output p.d.; sensor resistance changes, shifting voltage division. State circuit design and expected direction of change.
What to do in an assessment
- Draw circuit symbols, put ammeter in series and voltmeter in parallel; identify controls and make one change at a time.
- Worked example: 2.0 A flows for 15 s: Q=It=30 C. With 4.0 V across a resistor, R=V/I=2.0 Ω.
- Describe I–V practical: vary supply/variable resistor, measure paired I,V values, reverse polarity where relevant, plot axes with units and infer component behaviour.
In plain language
Charge flow, energy per charge and resistance let you predict and test circuit behaviour; wiring determines how current and potential difference are shared.
Self-check
A 12 V supply is across a 4 Ω resistor. What current flows? How does an LDR respond when light intensity rises?
Show the answer
I=V/R=12/4=3 A. An LDR’s resistance decreases as light intensity rises.
- Core
Scope: Core · §2c Chapter P1–P8 / Appendix 5d–5h; exact source-leaf scope recorded in inventory.sourceLeafCrosswalk
Open revision guidance
What to know
- P3.4.1–3 — Current through a device transfers energy from supply to device/surroundings. P=E/t and E=QV. Larger charge or p.d. means more transferred energy; 1 C through 1 V transfers 1 J.
- P3.4.4a–b — P=VI and P=I²R; example 12 V × 2 A =24 W, or 2²×6 Ω=24 W. Use appropriate equation and units.
- P3.4.5–6 — Shared Appendix relation P3.4.5: ideal transformer input power equals output power, VpIp=VsIs. P3.4.6: transmitting the same power at higher voltage lowers current and I²R cable losses. Topic application is P3.7.6–8 (separate Physics qualification): a transformer has primary/secondary coils on an iron core; changing primary current creates changing magnetic field and induces p.d./current in secondary. P3.7.8a [Higher Tier only] applies power balance to compare primary and secondary; P3.7.8b [Higher Tier only] applies Vp/Vs=Np/Ns. Do not mistake the shared equation P3.4.5 for the tier of the P3.7.8a transformer application. Example Np=1000, Ns=100, Vp=230 V gives Vs=23 V; ideal power conservation determines secondary current.
- P3.5.1–4 — Like magnetic poles repel, unlike attract. Field is the region where a magnet experiences force; field lines show direction (north-seeking test pole direction) and strength (closer lines stronger), and never cross. Plot with compass or iron filings; identify Earth’s field. Permanent magnets retain magnetisation; induced magnets become magnetised in a field, often temporarily.
- P3.5.5–8 — Current produces magnetic field. Around a straight wire field lines are concentric circles; direction from right-hand grip rule. Field strength increases with current and decreases with distance. A coil/solenoid field resembles a bar magnet; more turns, greater current and iron core strengthen an electromagnet.
- P3.5.9 [Higher Tier only; separate Physics qualification] — In a loudspeaker/headphone, alternating current in a coil interacts with a permanent-magnet field; force reverses with current, vibrating coil/diaphragm and creating sound.
- P3.6.1–2 [Higher Tier only] — A magnet and current-carrying conductor exert equal/opposite interaction forces because their fields interact. Fleming’s left-hand rule: first finger field (N to S), second finger conventional current, thumb force/motion; mutually perpendicular.
- P3.6.3 [Higher Tier only] — For a straight wire perpendicular to field, F=BIl. Example B=0.20 T, I=3.0 A, l=0.10 m gives F=0.060 N. If not perpendicular, this simple GCSE relation uses the perpendicular conductor length.
- P3.6.4 [Higher Tier only] — Opposite sides of a rectangular current-carrying coil experience opposite forces, producing a turning effect; reversing current or field reverses rotation. The source does not require detailed motor construction.
- P3.7.1–5 [Higher Tier only; separate Physics qualification] — Changing magnetic field through a conductor induces p.d.; changing direction reverses it. A moving-coil microphone has vibrating diaphragm/coil in permanent field: sound pressure moves coil, inducing varying p.d./current. Alternator output changes sign each half-turn, yielding alternating p.d.-time graph. A dynamo uses a split-ring commutator to reverse coil connections each half-turn, producing unidirectional (pulsating) output; sketch a.c. alternating above/below zero and d.c. on one side of zero.
- P3.7.6–8 [Higher Tier only; separate Physics qualification] — A transformer uses changing current in primary, changing core flux and induced secondary p.d.; steady d.c. does not sustain transformer induction. Apply power and turns ratios to a transformer and explain grid efficiency. Both P3.7.8a application of the power equation and P3.7.8b turns-ratio application are Higher-only; the corresponding power-balance relationship is also listed separately as shared P3.4.5 in Appendix 5h.
What to do in an assessment
- Trace a motor/generator energy pathway and distinguish motor effect (current + field gives force) from induction (changing flux gives p.d.).
- Worked transformer: 230 V primary with 1000 turns and 200 turns secondary gives 46 V. Ideal input power 115 W means secondary current 115/46=2.5 A.
- In an induced-output graph, state sign, peak/zero intervals and how speed/field strength/turns change magnitude or frequency.
In plain language
Magnetic fields can exert forces or induce voltage when flux changes. This underpins motors, microphones, generators, transformers and efficient electricity distribution.
Self-check
Why does a transformer need changing current, and what happens to current when an ideal transformer steps voltage up?
Show the answer
Changing current makes changing magnetic flux that induces p.d. in the secondary; at approximately conserved power, higher secondary voltage means lower secondary current.
Topic group
P4 Explaining motion
- Core
Scope: Core · §2c Chapter P1–P8 / Appendix 5d–5h; exact source-leaf scope recorded in inventory.sourceLeafCrosswalk
Open revision guidance
What to know
- P4.1.1–4 — Newton’s third law: interacting objects exert forces equal in size, opposite in direction, same type and on different objects. Interactions include gravity, electrostatic, magnetic and contact (normal force/friction). Draw paired force vectors on separate objects; do not cancel a pair on one free-body diagram. Friction opposes relative sliding/tendency to slide; normal contact force acts perpendicular to surface.
- P4.1.5–7 — Weight is gravitational force on mass; measure with calibrated spring/top-pan balance in newtons. W=mg, with g≈10 N/kg near Earth (or specified value). Example 2.0 kg has W≈20 N.
- P4.2.1–5 — Average speed=distance/time. Distance is path length; displacement is change in position with direction. Speed is scalar; velocity is speed with direction. Typical scales include walking ~1.5 m/s, running ~3 m/s, cycling ~5 m/s, car ~25 m/s, sound in air ~330 m/s and wind about 5–10 m/s (stronger winds can be higher). Measure distance and time; use a trolley down a ramp with light gates/video or measured distance/time.
- P4.2.4–6 — Convert m/s↔km/h (×3.6 or ÷3.6); calculate acceleration a=(v−u)/t and investigate trolley acceleration using a ramp, timer/light gates and known intervals; repeat. Distance–time gradient=speed; velocity–time gradient=acceleration. P4.2.7 [Higher Tier only] — For constant acceleration use v²−u²=2as; the equation itself is listed unbold in Appendix 5h, but its P4.2.7 topic outcome application is Higher-only. P4.2.8–9 — Draw/use distance- and speed/velocity-time graphs and interpret line/slope in context. P4.2.10 [Higher Tier only] — Interpret enclosed area in a velocity–time graph as displacement (distance when motion stays in one direction). P4.2.11 — Recall free-fall acceleration ≈9.8 m/s²≈10 and estimate everyday acceleration from speed change/time.
- P4.3.1–2,6 — Describe forces on an isolated object and draw free-body diagrams; resultant force is vector sum. Balanced forces mean equilibrium/zero resultant and constant velocity; unbalanced force changes velocity. Newton’s first law: zero resultant means rest or uniform straight-line motion. P4.3.3 [Higher Tier only] — Use scale vector diagrams to add forces and show resultant/equilibrium, within source limits of parallel and perpendicular vectors. P4.3.4–5 [Higher Tier only] — Momentum p=mv; total momentum is conserved in an isolated collision. Newton’s second law in momentum form Δp=FΔt. Example 0.20 kg ball changes velocity from +10 to −5 m/s: Δp=0.20(−5−10)=−3.0 kg m/s; over 0.10 s, mean force=−30 N (the equation is also Higher-only in Appendix 5h). P4.3.7 [Higher Tier only] — Circular-orbit motion has constant speed but changing velocity because force changes direction.
- P4.3.4–5 [Higher Tier only] — Momentum p=mv; conservation: total momentum before=after in an isolated system. Newton’s second law in momentum form Δp=FΔt. Example 0.20 kg ball changes velocity from +10 to −5 m/s: Δp=0.20(−5−10)=−3.0 kg m/s; over 0.10 s, mean force=−30 N. P4.3.5 is Higher-only in Appendix 5h.
- P4.3.8–10 [separate Physics qualification, shared Foundation/Higher] — A force can rotate an object about a pivot. Moment M=F×perpendicular distance to pivot; 20 N at 0.30 m gives 6.0 N m. Levers and gears transmit/multiply turning effects. P4.3.11–12 [Higher Tier only] — Inertial mass measures resistance to acceleration and is defined by m=F/a; Newton’s second law F=ma. P4.3.13 [shared] — Apply equations linking force, mass, velocity, acceleration and momentum to explain relationships; choose the relation matching the stated process and check units.
- P4.3.14–15 — Measure reaction time by catching a dropped ruler or using a stimulus-response timer; repeat. Stopping distance=thinking distance+braking distance. Thinking distance rises with speed and reaction time; braking distance rises with speed and depends on brakes, tyres, road, mass/load and friction. P4.3.16 — Large deceleration causes large force and injury risk. Worked typical-road estimate: a 1200 kg car slowing from 20 m/s to 0 in 4.0 s has a=(0−20)/4=−5.0 m/s² and F=ma=−6000 N, opposite travel; lengthening the stop time reduces average force for the same momentum change. P4.3.17–18 [separate Physics qualification] — Given road data, estimate emergency stopping distances across speeds and estimate acceleration/force using speed, time and mass. Illustrative comparison with reaction time 0.70 s and measured braking deceleration 6.0 m/s²: at 10, 20, 30 m/s, thinking distances are 7, 14, 21 m; braking distance v²/(2a) is about 8, 33, 75 m; totals are about 15, 47, 96 m. Doubling speed doubles thinking distance but approximately quadruples braking distance in this constant-deceleration model. These are calculations from stated example assumptions, not universal stopping-distance data. Seatbelts, airbags, helmets and crumple zones lengthen collision time/reduce peak force.
- P4.4.1–9 — Work transfers energy when force moves an object along its line of action: W=Fs. Lifting increases GPE; moving/accelerating increases KE; friction transfers energy to thermal stores. KE=½mv²; GPE=mgh. Example: 2 kg raised 3 m at g=10 gains 60 J GPE. 100 N moving 4 m along its force transfers 400 J. Power P=E/t. For a projected object/up slope, obstacle collision, constant-force acceleration or slowing vehicle, name all changing stores and dissipated energy; total energy conserved. Convert 1 N m=1 J.
What to do in an assessment
- For graphs, label axes and units; identify whether slope or area answers the question. Show direction signs in velocity/momentum calculations.
- Worked stopping calculation: at 20 m/s with 0.8 s reaction time, thinking distance=16 m. If braking distance is 24 m, total stopping distance=40 m.
- Plan a safe practical using repeat readings, suitable timing/distance apparatus and controlled ramp/surface; explain limitations and improvements.
In plain language
Forces change velocity or shape; motion graphs, Newton’s laws and energy/momentum equations quantify what happens, especially in collisions and road safety.
Self-check
A 1000 kg car slows from 20 m/s to rest in 4 s. Find acceleration and resultant force.
Show the answer
a=(0−20)/4=−5 m/s²; F=ma=1000×(−5)=−5000 N, opposite the motion.
Topic group
P5 Radioactive materials
- Core
Scope: Core · §2c Chapter P1–P8 / Appendix 5d–5h; exact source-leaf scope recorded in inventory.sourceLeafCrosswalk
Open revision guidance
What to know
- P5.1.1–4 — Rutherford alpha scattering: most alpha particles passed through thin foil, some deflected sharply and a few rebounded. Infer atom mostly empty space with tiny, dense, positively charged nucleus; electrons occupy surrounding region. This evidence replaced the diffuse positive-charge model. Isotopes share proton number but differ in neutron number; use nuclide notation A over Z X, where A=protons+neutrons and Z=protons.
- P5.1.5–8 — Radioactive decay is random for an individual unstable nucleus; in a large sample a predictable fraction decays each interval. Alpha = helium nucleus (2p,2n), strongly ionising/short range; beta = fast electron, medium penetration; gamma = EM radiation, weakly ionising/high penetration. Use nuclear equations conserving nucleon and proton number; alpha decay lowers A by 4 and Z by 2, beta-minus leaves A unchanged and raises Z by 1, gamma changes neither. Some decays emit a neutron; represent it with A=1,Z=0 and conserve both totals. Background count must be measured and subtracted from source-plus-background.
- P5.1.9–12 — Detect count rate with Geiger–Müller tube/counter, keeping geometry and source-detector distance fixed. Record background over a suitable interval, repeat source counts, subtract background; count is statistical and fluctuates. Half-life is time for activity/undecayed nuclei to halve; estimate from corrected count-rate graph/table, not one nucleus. Random-decay practical: collect repeated counts or use an analogue random process, plot fraction remaining vs intervals and explain statistical scatter; radioactive source work is teacher-controlled and follows radiation safety.
- P5.2.1–5 — Alpha is stopped by paper/skin but dangerous inside body; beta passes paper but is reduced by thin aluminium; gamma needs thick lead/concrete and is reduced rather than completely stopped. Contamination means radioactive material on/in body; it continues irradiating, especially hazardous internally. Irradiation is exposure without radioactive substance transferred; it ends when source removed. Nuclear radiation can kill/damage cells/cause cancer. Medical uses include tracers/imaging of organs, radiotherapy to destroy tumours, and controlled destruction of unwanted tissue; balance benefit/risk. Hazard depends on radiation type, activity/dose, distance, exposure time, shielding and half-life. Short half-life lowers persistence but activity may be high; choose penetrating radiation based on intended use.
- P5.3.1–4 [separate Physics qualification] Fission: neutron absorbed by unstable heavy nucleus (e.g. uranium/plutonium), which splits into two smaller nuclei and releases neutrons, ionising radiation and kinetic energy. Released neutrons can trigger further splits: chain reaction. Reactor control absorbs some neutrons with control rods; moderator slows neutrons; coolant transfers heat to make steam/turbine electricity. Fusion joins light hydrogen nuclei to helium, releasing energy; some mass becomes radiation/energy. Compare nuclear benefits (high reliable output, low operational CO₂) with waste, accident, mining/decommissioning and cost; fusion power generation is not yet routine commercial supply.
What to do in an assessment
- Balance nuclear equations by checking total top numbers (nucleons) and bottom numbers (protons) on both sides.
- Worked half-life: corrected count falls from 800 to 100 counts/min in 12 min: 800→400→200→100 is three half-lives, so t½=4 min.
- In a risk comparison separate exposure/contamination, name pathway, source and protective measure; use distance, shielding, time and containment appropriately.
In plain language
Atomic evidence explains the nucleus; decay, penetration and half-life help make safe, evidence-based uses of radiation and nuclear energy.
Self-check
What is the difference between contamination and irradiation? Why subtract background count?
Show the answer
Contamination transfers radioactive material onto/into an object; irradiation exposes it to radiation without transfer. Background counts come from the surroundings, so subtract them to estimate source count rate.
Topic group
P6 Matter – models and explanations
- Core
Scope: Core · §2c Chapter P1–P8 / Appendix 5d–5h; exact source-leaf scope recorded in inventory.sourceLeafCrosswalk
Open revision guidance
What to know
- P6.1.1–2 — Density ρ=m/V; measure mass with a balance and volume from dimensions/geometry, liquid displacement for irregular solids, or measuring cylinder for liquid. Example 240 g/80 cm³=3.0 g/cm³ (3000 kg/m³); keep units consistent.
- P6.1.3–5 — Heating transfers energy to internal energy and may raise temperature or change state. Specific heat capacity c is energy per kg per °C: ΔE=mcΔT. Measure electrical energy (VIt or Pt), mass and temperature rise; insulate, stir, use thermometer/data logger, allow even heating and minimise losses. Example 0.50 kg water, c=4200 J/kg°C, rise 10°C: 210 kJ.
- P6.1.4–6 — Specific latent heat L is energy per kg to change state without temperature change. E=mL. Heating curve has rising-temperature sections and flat melting/boiling plateaus; energy during plateau changes particle arrangement/separation, not average kinetic energy. Example 0.20 kg melting with L=334 kJ/kg needs 66.8 kJ.
- P6.1.7–8 — Describe all stores/transfers: kettle electrical→thermal/internal plus surroundings; slowing car kinetic→thermal/sound; thrown object kinetic↔gravitational; obstacle collision dissipates energy. Use relevant mechanical, electrical, thermal and state-change equations; conservation applies to total system energy.
- P6.2.1–4 — Solid particles close, ordered, vibrate; liquid particles close, disordered, slide; gas particles far apart, move freely. Different spacing explains density differences. Physical changes (melt, freeze, evaporate, condense, sublime) conserve mass and are reversible without changing substance identity; distinguish chemical change. Heating increases particle kinetic energy/temperature between state changes; at melting/boiling energy changes arrangement/separation. Gas temperature relates to average kinetic energy; at constant volume hotter gas particles move faster and collide harder/more often, increasing pressure (qualitative).
- P6.3.1–4 — Stretching, bending or compression requires opposing forces. Elastic deformation returns when load removed; plastic deformation is permanent. Particle spacing/bond forces change under stress. Measure spring extension from unloaded length using ruler and add known masses/forces; plot force-extension. Linear means proportional; rubber may be elastic but nonlinear. Use a clamp stand, eye protection and do not overload.
- P6.3.5–7 — Hooke relation F=kx within linear range; k in N/m and x extension in m. Example 4 N /0.020 m =200 N/m. Work is area under force-extension graph (triangle for linear spring: ½Fx). Elastic energy E=½kx². Beyond proportional limit do not apply linear formula. Compare with loading/unloading curves and repeat.
- P6.4.1–5 [separate Physics qualification] — Fluid pressure acts normal to every surface; p=F/A. Gas pressure comes from particle collisions. At constant temperature, for fixed gas mass pV=constant (Boyle relationship): compression reduces volume and raises pressure; example p1V1=p2V2. Explain with more frequent wall collisions. Atmospheric pressure acts all directions and decreases with altitude because less air lies above.
- P6.4.6 — Model atmosphere as a column of air; atmospheric pressure is caused by air weight and decreases with altitude. P6.4.7 [Higher Tier only; separate Physics qualification] — Explain that liquid pressure rises with depth and density because of the weight of liquid above. P6.4.8 [Higher Tier only] — Apply Δp=ρgh to calculate pressure differences: for water at 2 m, ρ=1000 kg/m³ and g=10 N/kg gives 20,000 Pa. P6.4.9–10 [Higher Tier only] — Greater pressure on an immersed object’s lower surface than its upper surface gives an upward resultant (upthrust), reducing apparent weight. Whether it floats or sinks depends on weight, upthrust, object density, fluid density, shape/volume and amount of fluid displaced; floating is equilibrium when buoyancy equals weight.
- P6.5.1 [separate Physics qualification, shared Foundation/Higher] — Solar system has Sun, planets, moons and artificial satellites; distinguish planets orbiting stars, natural moons orbiting planets and human-made satellites. P6.5.2–3 [Higher Tier only; separate Physics qualification] — Gravity supplies centripetal force in circular orbit, changing velocity direction while speed may stay constant; if speed changes, the radius must also change for a stable orbit (qualitative). P6.5.4 [shared] — Solar system formed from dust and gas drawn together by gravity. P6.5.5–6 [Higher Tier only] — Work compressing gas increases its internal energy/temperature (e.g. bicycle pump); in a collapsing solar nebula, heating enables hydrogen fusion, whose outward effect balances gravitational collapse in the Sun.
- P6.5.7–9 [Higher Tier only] — Receding galaxies’ spectral lines shift to longer (red) wavelengths: red-shift indicates recession. Greater distance correlates with greater recession speed, evidence space itself is expanding; this observation supports an expanding-Universe model and leads to the Big Bang explanation. P6.5.10–12 [shared Foundation/Higher; separate Physics qualification] — The early Universe model is about 14 billion years old; cosmic microwave background is remnant radiation supporting the model. Models gain confidence as red-shift, galaxy-distance and CMB evidence converge; assess limitations and improved telescope observations rather than treating a model as direct observation.
What to do in an assessment
- Show equation, substitution, unit conversion and answer; use kg, m, m², m³, J, Pa and seconds consistently.
- Worked gas example: 100 kPa × 0.030 m³ = p₂ × 0.020 m³, so p₂=150 kPa (constant temperature, fixed gas mass).
- For a graph use slope/area only when axes and units support it; state assumptions (e.g. constant temperature, linear spring range).
In plain language
Particle and energy models connect heating, state changes, material deformation, fluids and astronomy to measurable evidence.
Self-check
A 0.40 kg block of mass displaces 0.00050 m³ of water. What is its average density, and will it float in water?
Show the answer
Density=0.40/0.00050=800 kg/m³, less than water’s approximate 1000 kg/m³, so it can float when displaced-water upthrust balances its weight.
Topic group
P7 Ideas about Science
- Core
Scope: Core · §2c Chapter P1–P8 / Appendix 5d–5h; exact source-leaf scope recorded in inventory.sourceLeafCrosswalk
Open revision guidance
What to know
- IaS1.1–3 — Use scientific theory/tentative explanation to form a testable hypothesis (“because…”) and prediction (“if…then…”); distinguish explanation from prediction. Choose quantities and measurement method, know what each quantity means and how it is determined; choose apparatus for required range/resolution and justify precision, accuracy and validity.
- IaS1.4–8 — Identify independent, dependent and control variables and how to hold controls constant; choose adequate range and repeats/sample size. Plan logically sequenced procedures for observations, producing/characterising substances, testing hypotheses, checking data or exploring a phenomenon. Identify hazards, risks and mitigations. Communicate rationale/method with correct vocabulary, labelled diagrams, graphs, numerical and symbolic forms.
- IaS2.1–6 — Present observations/data in suitable tables, diagrams and graphs; process in SI units, use nomenclature where relevant, prefixes/powers of ten, unit conversions and suitable significant figures. Translate words/tables/graphs/equations appropriately.
- IaS2.7–8 — Select axes/scales and graph type, plot accurately, draw best fit, show uncertainty/range bars; find mean/range, identify trends, read gradient, interpolate/extrapolate only within justified model. Distinguish precision (spread/resolution), accuracy (closeness to true value), repeatability (same operator/setup) and reproducibility (different operator/setup).
- IaS2.9–12 — Evaluate data quality and random/systematic error. Retain an outlier unless evidence shows an error; compare repeats and explain decisions. Improve method with a specific change linked to improved accuracy/precision/repeatability/reproducibility; propose useful follow-up. Interpret graphs/data to infer and conclude with evidence and uncertainty. Agreement increases confidence, does not prove hypothesis; disagreement reduces confidence or suggests revision.
- IaS3.1–2 — Correlation is association, not by itself causation. Identify correlation, propose confounders and plausible mechanism; isolated cases cannot establish/disprove correlation. Scientific explanations are creative, separate from raw data, tested and revised as evidence/technology develops; theories are broad, repeatedly supported explanations. Example: atomic model changed after scattering evidence.
- IaS3.3–4 — Peer review means other scientists scrutinise methods, evidence and reasoning before publication/acceptance; replication and reproduction strengthen trust. Models (representational, spatial, descriptive, computational, mathematical) solve problems, explain and predict, but state limitations and where model differs from reality.
- IaS4.1–2 — Explain positive applications and identify risks/unintended effects of technology.
- IaS4.3–4 — Identify benefits and risks to different people/groups, who chooses/accepts risk, perceived vs statistically calculated risk, and justify a course of action with evidence and context. Different social, personal, economic or environmental contexts can justify different decisions.
- IaS4.5–6 — Separate empirically answerable questions from ethical/value questions; name the ethical issue and summarise differing views. Scientists should communicate findings clearly to public, peers and decision makers.
- IaS4 cross-links — Apply to radiation, climate evidence, energy resources, nuclear power, road safety and technology decisions; distinguish evidence-based physical claims from value judgements.
What to do in an assessment
- Structure an investigation: question/hypothesis → prediction → variables and controls → apparatus/range/repeats → safe method → table/graph → processing → conclusion/evaluation.
- When evaluating a claim write: observation, trend/correlation, possible mechanism, alternative explanations, evidence quality, uncertainty, conclusion and confidence.
- Worked example: two variables rise together, but a third factor changes both. Call it correlation until a mechanism and controlled evidence support causation.
In plain language
Ideas about Science are practical habits for planning fair tests, handling evidence, evaluating models and making transparent decisions.
Self-check
Why does a repeatable result not automatically prove a hypothesis?
Show the answer
Repeatability improves confidence that the result is reliable, but systematic error, confounding factors or another explanation may remain; evidence supports, rather than proves, a hypothesis.
Topic group
P8 Practical skills
- Core
Scope: Core · §2c Chapter P1–P8 / Appendix 5d–5h; exact source-leaf scope recorded in inventory.sourceLeafCrosswalk
Open revision guidance
What to know
- P8 framework — Centres must provide at least eight practical activities, one opportunity across each PAG 1–8, and learners must have opportunities to use every listed apparatus/technique. The activities are preparation for written-paper practical questions, not coursework; at least 15% of written-question marks assess practical skills. This guide teaches written methods, not a claim that activities were performed or CPAC/local delivery met.
- PAG1 Materials — Measure mass (balance), dimensions/volume (rule/calipers/measuring cylinder/displacement), density; force-extension using masses, clamp stand, spring and ruler; record original length and extension, plot force-extension and identify linear/proportional limit. Risks: falling masses, secure stand, eye protection.
- PAG2 Forces — Use force meter/newton meter, masses, pivot/metre rule, spring and clamp; investigate moments/equilibrium or force-extension. Measure perpendicular distance from pivot; vary one force/distance, repeat; secure loads and keep feet clear.
- PAG3 Motion — Measure distance and time with ruler/tape, stopwatch, ticker timer/light gates/data logger or video; trolley on ramp for speed/acceleration. Use known distance, repeated timing, light gates to reduce reaction-time error; control ramp angle and release point. Plot distance/time or velocity/time.
- PAG4 Measuring waves — Ripple tank, dipper, lamp/strobe, screen/ruler; measure wavelength over several crests and frequency/time, derive speed v=fλ. Measure sound speed over known distance/echo time. Keep depth and source setting controlled; avoid parallax and use long baselines.
- PAG5 Energy — Heater/electrical supply, ammeter, voltmeter, balance, thermometer/data logger, insulation, stopwatch; find specific heat capacity from supplied energy and temperature rise; compare energy/power or efficiency. Insulate, stir, measure mass, minimise heat loss; handle hot water/electrics safely.
- PAG6 Circuit components — Low-voltage d.c. supply, ammeter in series, voltmeter parallel, variable resistor, switch, lamp/diode/LDR/NTC. Sweep potential difference, record paired I,V; reverse polarity for diode; control light/temperature for component curve; plot I–V and identify nonlinear response. Switch off to prevent heating.
- PAG7 Series and parallel circuits — Build symbolic d.c. circuits with cells/supply, switches, lamps/resistors, ammeters and voltmeters; investigate current/p.d., equivalent resistance, lamp brightness or potential divider/sensors. Ammeter series, voltmeter parallel, fixed supply and component; use low-voltage supply and avoid short circuits.
- PAG8 Interactions of waves — Ray box/laser with mirror, glass block/prism, lenses, pins, paper, protractor; investigate reflection/refraction/dispersion and measure angles from normal. Use narrow beam, mark incident/emergent rays, repeat angles. Also examine wave transmission/reflection at interfaces. Never shine laser into eyes.
- Common apparatus and measurement — Select suitable range/resolution; zero instruments; read scale at eye level; repeat, record units and raw data, identify anomalous readings without automatic rejection. Draw labelled apparatus and circuit diagrams, make tables, graph with sensible scales/best fit, estimate uncertainty, use equations and evaluate controls.
- Written practical assessment — Questions can ask apparatus choice, variables, method, safety, data table/graph, calculation, conclusion, uncertainty, anomaly, improvement or limitation. Practical experience does not remove need to explain method and analyse unfamiliar data.
- §3a forms of assessment — Linear qualification, 100% externally examined; four 90-mark papers, each 1 h 45 min. J259/01 and /02 are Foundation breadth/depth; /03 and /04 Higher breadth/depth. Each paper is 50% of that tier qualification and samples P1–P7. Breadth covers the whole specification with short structured/calculation/practical questions and no extended-response item. Depth covers the whole specification, short structured/calculation/practical questions and at least two 6-mark extended responses assessed with levels of response. Candidates answer all questions.
- Read the paper scopes together: the §2a–2b overview says both papers assess all eight chapters, including P8 practical skills; §3a describes the sampled subject content as P1–P7 and separately requires practical-skill questions. P8 is therefore not omitted from either paper. Prepare practical methods, apparatus, data analysis and evaluation alongside the P1–P7 subject content; at least 15% of the written assessment tests practical skills.
- §3b assessment objectives — AO1 knowledge/understanding of scientific ideas and techniques (40% overall: 40 Foundation/40 Higher); AO2 application of ideas and enquiry/techniques (40%); AO3 analysis to interpret/evaluate, judge/conclude and develop/improve procedures (20%). By paper as % overall: Foundation breadth 24/18/8 AO1/AO2/AO3; Foundation depth 16/22/12; Higher breadth 24/18/8; Higher depth 16/22/12. Thus practical competence is assessed through knowledge, application and analysis, not a separate coursework grade.
- §3c full command-word glossary — analyse: separate information into components and identify their characteristics; also discuss pros and cons of a topic/argument and make reasoned comment. Calculate: generate a numerical answer, with workings shown. Choose: select from a list/alternatives. Classify: assign to a category/group. Compare and contrast: identify similarities and differences. Complete: add words, numbers, labels or plots to complete a sentence, table, diagram or graph. Conclude: make a decision after reasoning. Construct: write or draw the requested item. Convert: change a defined item to another defined item. Deduce: use knowledge and/or supplied data to work something out. Define: use knowledge to state a given term’s meaning. Describe: set out facts/characteristics; describe processes by what happens and when/where. Design: plan/present ideas showing layout, function, workings, object, system or process. Determine: obtain a solution by following procedures or a numerical value by calculations. Discuss: give an account addressing a range of ideas/arguments. Draw: produce a sufficiently detailed, labelled diagram to illustrate the answer. Estimate: assign an approximate value. Evaluate: make a qualitative judgement considering factors and available knowledge/experience/evidence. Explain: give reasons/mechanisms addressing why/how. Find: obtain a solution by procedures or numerical value by calculations (more common in Foundation). Give: short answer, no explanation unless separately requested. How: in what way? Identify: recognise, list, name or otherwise characterise. Illustrate: make clear using examples or diagrams. Justify: present a reasoned case for actions/decisions. Label: add names/identifying words or symbols to a diagram. Measure: establish a value using a suitable measuring instrument or technique. Name: provide appropriate word(s)/term(s). Outline: describe main characteristics/points. Plan: consider, set out and communicate what is to be done. Plot: translate data into a suitable graph/chart with labelled axes. Predict: judge an event/action that will happen as a result of knowledge, experience or evidence. Recall: use specification knowledge to remember a relevant key fact. Select: carefully choose what is most suitable for a task or purpose. Show: write details, steps or calculations to prove a fact/answer. Sketch: simple freehand illustration of the general point, no detail required; for a graph, general curve shape without precise points. State or define: express precisely the nature, state or meaning. Suggest: give possible alternatives or propose an idea/plan for consideration. Use/using: base the answer on information given in the question. What: request information clarified by context. Which: identify an object, word or explanation. Why: for what reason? Write: present the required information (e.g. balanced equations). The exact expected response depends on context; read the full question carefully.
- PAG1–5 shared apparatus requirement — In each of PAG1–5, use appropriate apparatus to make and record a range of measurements accurately, including length, area, mass, time, volume and temperature; use measurements to determine density (PAG1), observe force effects/spring extension (PAG2), measure motion/speed/acceleration (PAG3), observe waves in fluids and solids and choose apparatus for wave speed/frequency/wavelength (PAG4), and safely measure energy transfer/work and associated values (PAG5). The specification permits different suitable apparatus and centre-devised activities, but every listed technique must be covered.
- §3d tiers — Foundation assesses grades 5–1; Higher assesses grades 9–4. An allowed grade 3 may be awarded to Higher candidates a small number of marks below the 3/4 boundary. A candidate enters one tier, taking both components at that tier.
- §3e qualification time — Total qualification time is 140 hours, including guided learning, preparation, study and assessment; guided learning time is 120–140 hours.
- §3f–g availability and language — The qualification is available in England; check the Wales QIW portal or Northern Ireland performance-measures/NIEFQAN list for current availability. Qualification, assessment materials and candidate work are English-only.
- §3h–i examination availability and retakes — One examination series is available each year in May/June; the qualification has been certificated from June 2018 onward. All examined components must be taken in the same examination series at the end of the course. Learners may retake as many times as they wish, but must retake all components in the tier of entry.
- §3j extended response — Depth papers include asterisked questions marked using levels-of-response schemes. Candidates must construct and develop a sustained line of reasoning that is coherent, relevant, substantiated and logically structured; the Depth paper includes at least two six-mark extended responses.
- §3k synoptic assessment — All papers contain a synoptic element: connect areas of Physics, apply knowledge from multiple areas to a situation, draw together ideas in planning investigations and analysing/evaluating data.
- §3l qualification result — Add the marks from the two components taken to obtain the total weighted mark, then compare it with qualification-level grade boundaries for the selected entry option and examination series to determine the overall grade.
What to do in an assessment
- On any practical question identify independent/dependent/control variables, apparatus and range, ordered steps, repeats, safety, data handling and a specific improvement.
- Example wave practical: count 10 crests in 5 s → f=2 Hz; 5 wavelengths span 0.40 m → λ=0.080 m; speed=0.16 m/s.
- Give quantitative reasons for improvements (e.g. time 20 oscillations rather than 1 to reduce percentage timing uncertainty).
In plain language
PAGs describe families of apparatus and methods. Written exams test whether you can choose, explain and evaluate those methods using data.
Self-check
Why time many oscillations or crests rather than one when measuring frequency?
Show the answer
A longer total interval reduces the relative effect of stopwatch/reaction-time uncertainty; divide the count by total time and repeat.
Topic group
Appendix skills
- Core
Scope: Core · §2c Chapter P1–P8 / Appendix 5d–5h; exact source-leaf scope recorded in inventory.sourceLeafCrosswalk
Open revision guidance
What to know
- Appendix 5d units — Use standard SI units: m, kg, s, A, K/°C where appropriate, m/s, m/s², N, J, W, C, V, Ω, Hz, Pa, kg/m³, T. Convert prefixes and compound units before substitution; 1 N m=1 J, 1 kWh=3.6 MJ, 1 km/h=1/3.6 m/s.
- Appendix 5e mathematical skills — Use arithmetic, ratios, fractions, percentages, standard form, significant figures, estimates, unit conversion, direct/inverse proportion, equations/rearrangement and graphical methods. Use consistent units, sensible precision and checks for magnitude.
- Appendix 5f quantitative requirements — M1 arithmetic/standard form/ratios/percentages/estimation; M2 handling data including means, range, significant figures, uncertainty and graph reading; M3 equations and relationships; M4 graphs including gradients/areas and interpretation; M5 geometry/scale diagrams and measuring. Apply each in named physics contexts rather than memorising labels.
- Appendix 5g health and safety — Identify hazard, who may be harmed, likelihood/severity and control; follow apparatus/source instructions, use low voltage, secure loads, protect from heat/laser/radiation and never handle radioactive sources unless authorised. Risk controls do not imply zero risk.
- Appendix 5h equations to recall and apply (standard SI units): P1.3.6 v=fλ; P2.1.3 E=Pt; P2.1.8 efficiency=useful energy/total energy; P3.2.2 Q=It; P3.2.4a V=IR; P3.3.1 V=W/Q; P3.4.2/P4.4.9 P=E/t; P3.4.3 E=QV; P3.4.4a P=VI; P3.4.4b P=I²R; P4.1.7 W=mg; P4.2.1 v=s/t; P4.2.6a a=(v−u)/t; P4.3.4/P4.3.13 p=mv; P4.3.9 M=Fd; P4.3.12/P4.3.13 F=ma; P4.4.2 W=Fs; P4.4.3 Ek=½mv²; P4.4.4 Ep=mgh; P6.1.2 ρ=m/V; P6.1.5a ΔE=mcΔθ; P6.1.6 E=mL; P6.3.5 F=kx; P6.4.2 p=F/A. P4.4.9 and P4.3.13 are repeated source references to the same relationships; they are not omitted simply because formula symbols repeat.
- Appendix 5h relationships to select and apply from the supplied list: P3.6.3 F=BIl [Higher Tier only]; P3.4.5 VpIp=VsIs and P3.7.8a VpIp=VsIs (equation shared, but P3.7.8a transformer application Higher-only); P3.7.8b Vp/Vs=Np/Ns [Higher Tier only]; P4.2.7 v²−u²=2as (equation shared, but P4.2.7 topic outcome Higher-only); P4.3.5 Δp=FΔt [Higher Tier only]; P6.1.5a ΔE=mcΔθ; P6.1.6 E=mL; P6.3.7 E=½kx²; P6.4.5 pV=constant at constant temperature; P6.4.8 Δp=ρgh. Except the three explicitly bold relationships above, the supplied-list equations are shared formula knowledge, even when a corresponding topic outcome is Higher-only. Preserve vector signs for momentum/velocity and use magnitudes only when requested.
- Equation method — identify requested quantity, choose relation, rearrange before substitution, convert units, substitute with units, calculate and report appropriate significant figures. Check dimensional and physical plausibility. Efficiency may be ratio or percentage; kWh is energy, not power.
What to do in an assessment
- Worked example: P=VI with V=12 V,I=2 A → 24 W; in 30 s, E=Pt=720 J. Convert before using formulae.
- Rearrange algebraically rather than guessing; e.g. from v=fλ, f=v/λ. For graph gradients state units and meaning.
- Appendix 5h Higher equation boundary is explicit above; Foundation students are not assigned the three bold higher-only equations. Foundation and Higher both share the other listed required equations as indicated.
In plain language
Physics mathematics is choosing a valid relation, consistent units and a transparent calculation; equation boundaries follow J259’s own Appendix 5h.
Self-check
A 3.0 kg object accelerates at 2.0 m/s². Which relation gives force, and what is the result?
Show the answer
F=ma=3.0×2.0=6.0 N.
Topic group
Higher-tier supplement
- Higher
Scope: Higher · Examination tier: Higher Tier · §2a–2c tier tables and source-bold learning outcomes; Appendix 5h bold equation entries
Open revision guidance
What to know
- Tier rule — Foundation entry is J259/01 breadth plus /02 depth; Higher entry is /03 breadth plus /04 depth. Both papers at a selected tier assess the same qualification. Only specification statements and equations shown bold are Higher Tier only; separate-science topics P1.4, P3.1, P3.7, P5.3, P6.4 and P6.5 are within this separate Physics qualification, not Higher-only by virtue of their separate-science label.
- Higher-only source-bold clauses: P1.1.10; P1.2.2; P1.3.9–10; P1.4.6–8 (P1.4.9 is shared); P2.1.8 clause “describe ways to increase efficiency” (ratio itself shared); P3.5.9 and P3.6.1–4; P3.7.1–8a and 8b; P4.2.7 and 4.2.10; P4.3.3–5, 4.3.7, 4.3.11–12; P6.4.7–10; P6.5.2–3 and 5–9. P3.7.8a topic application is Higher although its equation row is shared; likewise P4.2.7 outcome is Higher while its Appendix 5h formula row is shared. Other outcomes are shared unless separate-science scope applies; that label alone does not make an outcome Higher. P4.3.8–10 are separate Physics but shared at both tiers.
- Appendix 5h Higher-only bold relationships: P3.6.3 F=BIl; P3.7.8b Vp/Vs=Np/Ns; P4.3.5 Δp=FΔt. The topic outcome P3.7.8a application is Higher even though its equation row is shared; likewise P4.2.7 topic outcome is Higher while its equation row is shared. P6.1.5a ΔE=mcΔθ and P6.1.6 E=mL are individual recall-and-apply equations.
- Tier tagging caution — Do not infer a whole topic/chapter is Higher from a bold outcome; do not downgrade separate-science outcomes or mark them Higher without source typography. Where a statement’s source bold formatting determines tier, the outcome-level annotations on the shared cards govern.
- P1.1.10 [Higher Tier only] — Oscillating current in a transmitting circuit produces radio waves. An incoming radio wave makes electrons oscillate in a conductor; the induced oscillating current is detected by a receiver circuit.
What to do in an assessment
- Check candidate tier before deciding which outcome to revise; use the complete shared course plus only the Higher additions for Higher entry.
- When answering a Higher-only calculation, show the equation and application; Foundation students should not be tested on those specifically marked equations.
In plain language
Higher students study the shared J259 course and source-bold additions; separate-science scope is part of J259 Physics B at both tiers unless the outcome itself is bold.
Self-check
Is every separate-science outcome automatically Higher Tier only?
Show the answer
No. Separate science defines the Physics qualification scope; only source-bold statements/equations are Higher-only.
Earlier topic checklist
These earlier topic ticks are separate from the reviewed points above and do not count towards that progress.
Physics topic list
This is a topic overview, not a complete specification checklist. Check the official course for all assessed content, options and your exam year.
The exact course specification for this overview has not been confirmed. Check the qualification code and any A/B pathway with your school before using this list.
Tick each item off as you revise. Ticks are saved on this device only.
These ticks keep your earlier topic checklist. They do not count towards the new reviewed requirements above. Its numbering may be internal; use the linked references above for the exact reviewed source requirements.
Foundation tier topics
Higher tier topics
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