AQA GCSE Physics Foundation: grade by grade

Every skill, from the first marks to the top grade. For each grade you also need the skills for the grades below it. Tick them off in the app's Notes section.

Grade 3

Grade 3 checklist (PDF)

Define a system A system is an object or a group of objects that you choose to study, e.g. a ball and the Earth. Energy stores and systems
Name the main energy stores Kinetic, gravitational potential, elastic potential, thermal (internal), chemical, magnetic, electrostatic and nuclear. Energy stores and systems
Recall the kinetic and gravitational energy equations E_k = ½ m v² and E_p = m g h: the specification says you must be able to recall both. Changes in energy
Name what affects the energy needed to heat The energy needed depends on the mass, the material and the temperature rise. Energy changes in systems
State the unit of power Power is measured in watts (W); 1 W is 1 joule transferred per second. Power
State the law of conservation of energy Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed. Energy transfers in a system
Identify useful and wasted energy transfers E.g. for a lamp, light is the useful output and heating the surroundings is wasted. Efficiency
List the main energy resources Fossil fuels (coal, oil, gas), nuclear fuel, bio-fuel, wind, hydro-electricity, geothermal, the tides, the Sun and water waves. National and global energy resources
Define a renewable energy resource A resource that is being (or can be) replenished as it is used. National and global energy resources
Name common components from their symbols Recognise the cell, battery, switch, lamp, resistor, ammeter and voltmeter symbols. Standard circuit diagram symbols
State that current is a flow of charge Electric current is a flow of electrical charge around a closed circuit. Electrical charge and current
Give the units of charge, current, time Charge in coulombs (C), current in amperes (A) and time in seconds (s). Electrical charge and current
State the unit of resistance Resistance is measured in ohms (Ω). Current, resistance and potential difference
Recall that an LDR's resistance falls in light The resistance of an LDR decreases as light intensity increases. Resistors
Tell series and parallel circuits apart Series: one loop, one path. Parallel: two or more branches connected across the same two points. Series and parallel circuits
State that mains electricity is ac The mains supply is an alternating current (ac) supply. Direct and alternating potential difference
Recall the UK mains frequency and pd The UK domestic supply has a frequency of 50 Hz and is about 230 V. Direct and alternating potential difference
Recall the colours of the three wires Live is brown, neutral is blue, earth is green and yellow stripes. Mains electricity
State the unit of power Power is measured in watts (W); 1 W is 1 joule per second. Power
Describe energy transfers in simple appliances e.g. a kettle transfers energy electrically from the mains to the thermal energy store of the water. Energy transfers in everyday appliances
Describe what the National Grid is A system of cables and transformers linking power stations to consumers. The National Grid
State how like and unlike charges interact The same type of charge repels; different types of charge attract. Static charge
Draw particle diagrams for the three states Solid: particles touching in regular rows; liquid: particles touching but jumbled; gas: particles far apart and random. Density of materials
Name the changes of state Melting, freezing, boiling, evaporating, condensing and sublimating. Changes of state
State that heating increases the particles' energy Heating a system transfers energy to its particles, so the energy they store increases. Internal energy
Describe the motion of gas molecules They are in constant random motion, moving in all directions. Particle motion in gases
Name the three particles in an atom Protons and neutrons are in the nucleus; electrons are arranged around the nucleus. The structure of an atom
State what atomic number means The atomic number is the number of protons in the nucleus. Mass number, atomic number and isotopes
Put the models of the atom in order Tiny spheres, plum pudding, nuclear model, Bohr's energy levels, then protons and neutrons. Development of the model of the atom
Name the types of nuclear radiation Alpha particles (α), beta particles (β), gamma rays (γ) and neutrons (n). Radioactive decay and nuclear radiation
Give precautions for handling radioactive sources Use tongs, wear gloves, keep the source in a lead-lined box and spend as little time near it as possible. Radioactive contamination
Define background radiation Radiation that is around us all the time, from natural and man-made sources. Background radiation
Define scalar and vector quantities A scalar has magnitude only; a vector has magnitude and an associated direction. Scalar and vector quantities
Define a force as a push or pull A force acts on an object because of its interaction with another object, and is measured in newtons (N). Contact and non-contact forces
Name examples of contact forces Friction, air resistance, tension and normal contact force act when objects are touching. Contact and non-contact forces
Define weight as the force due to gravity Weight is measured in newtons (N); mass is measured in kilograms (kg). Gravity
Define resultant force A single force that has the same effect as all the original forces acting together. Resultant forces
State that work done is energy transferred When a force moves an object through a distance, energy is transferred and work is done. Work done and energy transfer
Explain why more than one force is needed To stretch, bend or compress an object, forces must act on it in different directions. Forces and elasticity
Give examples of turning effects of forces Opening a door, turning a spanner and a see-saw all involve forces that cause rotation. Moments, levers and gears
State that fluids are liquids or gases Both liquids and gases are fluids and both exert pressure. Pressure in a fluid (p = F/A)
State that distance is a scalar Distance is how far an object moves; it does not involve direction. Distance and displacement
State that speed is a scalar Speed is the distance travelled per unit time and has no direction. Speed
Define velocity The velocity of an object is its speed in a given direction. Velocity
Describe motion from a distance–time graph A horizontal line means stationary; a straight sloping line means constant speed. Distance–time graphs
Recognise balanced forces on a diagram Equal-sized arrows in opposite directions mean the resultant force is zero. Newton's First Law
Define stopping distance as thinking plus braking Thinking distance is covered during the reaction time; braking distance is covered while the brakes act. Stopping distance
Recall typical reaction times Typical reaction times range from 0.2 s to 0.9 s. Reaction time
Name factors that increase braking distance Higher speed, wet or icy roads, worn brakes and worn tyres. Factors affecting braking distance
Give examples of transverse and longitudinal waves Transverse: ripples on water and all electromagnetic waves, such as light. Longitudinal: sound waves in air. Transverse and longitudinal waves
Label amplitude and wavelength on a diagram Amplitude: from the undisturbed position to a crest (or trough). Wavelength: one complete wave, e.g. crest to crest. Properties of waves
State what can happen at a boundary A wave can be reflected, absorbed or transmitted when it meets a boundary between two different materials. Reflection of waves
Name the parts of the EM spectrum in order Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays. Types of electromagnetic waves
State that EM waves are transverse EM waves are transverse waves that transfer energy from a source to an absorber. Types of electromagnetic waves
Name the EM waves that harm body tissue Ultraviolet, X-rays and gamma rays can have hazardous effects on human body tissue. EM waves: production and hazards
Match each EM wave to a use E.g. radio waves: television and radio; X-rays: medical imaging. Uses and applications of EM waves
Recognise the convex and concave lens symbols Convex: a line with outward-pointing arrowheads. Concave: a line with inward-pointing arrowheads. Lenses
Order the colours of the visible spectrum Red, orange, yellow, green, blue, indigo, violet; red has the longest wavelength. Visible light
State that all objects emit and absorb infrared All bodies, whatever their temperature, emit and absorb infrared radiation. Emission and absorption of infrared radiation
State that all bodies emit radiation Every object emits radiation; how much, and at which wavelengths, depends on its temperature. Perfect black bodies and radiation
State where a magnet's forces are strongest The magnetic forces are strongest at the poles: the north (seeking) pole and the south (seeking) pole. Poles of a magnet
Predict attraction or repulsion between two poles Like poles (N and N, or S and S) repel; unlike poles (N and S) attract. Poles of a magnet
Name the four magnetic materials Iron, steel, cobalt and nickel are always attracted by a magnet. Magnetic fields
State that a current produces a magnetic field When a current flows through a wire, a magnetic field is produced around the wire. Electromagnetism
List the objects in our solar system One star (the Sun), eight planets, dwarf planets such as Pluto, and moons that orbit planets. Our solar system
Name the galaxy our solar system is in Our solar system is a small part of the Milky Way galaxy. Our solar system
Order the first stages of a star's life Every star starts as a nebula, then becomes a protostar, then a main sequence star. The life cycle of a star
State the force that keeps objects in orbit Gravity provides the force that keeps planets, moons and artificial satellites in their orbits. Orbital motion and satellites

Grade 4

Grade 4 checklist (PDF)

Name the ways energy is transferred Mechanically (a force doing work), electrically (a current doing work), by heating and by radiation such as light. Energy stores and systems
Calculate gravitational potential energy Multiply mass (kg) × gravitational field strength (N/kg) × height (m) to get the energy in joules. Changes in energy
Define specific heat capacity The amount of energy needed to raise the temperature of 1 kg of a substance by 1 °C. Energy changes in systems
Define power Power is the rate at which energy is transferred, or the rate at which work is done. Power
Calculate power from energy and time Divide the energy transferred (J) by the time taken (s). Power
Give examples of energy being dissipated Friction heats moving parts, air resistance heats the air, and a motor makes sound. Energy transfers in a system
Calculate efficiency from energy values Divide the useful output energy by the total input energy. Efficiency
Sort resources into renewable and non-renewable Coal, oil, gas and nuclear fuel are non-renewable; all the others are renewable. National and global energy resources
Link energy resources to their uses The three main uses are transport, electricity generation and heating. National and global energy resources
Draw a simple series circuit correctly Use a ruler, straight wires and the correct symbols, with no gaps in the loop. Standard circuit diagram symbols
Recognise diode, LED, fuse and variable resistor Tell apart symbols that look alike, such as the diode and the LED, or the resistor and the fuse. Standard circuit diagram symbols
State what a circuit needs for current A closed circuit (complete loop) that includes a source of potential difference, such as a cell. Electrical charge and current
Calculate charge using Q = I t Multiply the current in amps by the time in seconds to get the charge in coulombs. Electrical charge and current
Describe how resistance affects current For a given potential difference, the greater the resistance, the smaller the current. Current, resistance and potential difference
Calculate pd using V = I R Multiply the current in amps by the resistance in ohms to get the pd in volts. Current, resistance and potential difference
Recall that a thermistor's resistance falls when hot The resistance of a thermistor decreases as temperature increases. Resistors
State the series and parallel rules Series: same current, pd shared. Parallel: same pd across each branch, branch currents add up. Series and parallel circuits
Add resistances in series Use R_total = R₁ + R₂. Series and parallel circuits
Name a source of direct pd Cells and batteries supply a direct potential difference. Direct and alternating potential difference
State the job of each wire Live carries the alternating pd from the supply, neutral completes the circuit, earth is a safety wire. Mains electricity
Explain what power means Power is the rate of energy transfer: the energy transferred each second. Power
Calculate power using P = V I Multiply the pd in volts by the current in amps to get the power in watts. Power
State what affects the energy transferred The power of the appliance and how long it is switched on for. Energy transfers in everyday appliances
Calculate energy using E = P t Power in watts × time in seconds gives energy in joules. Energy transfers in everyday appliances
State what a step-up transformer does It increases the potential difference from the power station to the transmission cables. The National Grid
State what a step-down transformer does It decreases the potential difference to a much lower value for domestic use. The National Grid
Describe charging by rubbing insulators Rubbing certain insulating materials together makes them electrically charged. Static charge
Describe what an electric field is The region around a charged object where another charged object experiences a force. Electric fields
Recall and use density = mass ÷ volume Substitute into ρ = m / V with mass in kg and volume in m³ to get a density in kg/m³. Density of materials
State that mass is conserved When a substance changes state the number of particles stays the same, so its mass does not change. Changes of state
Define internal energy The total kinetic energy and potential energy of all the particles (atoms and molecules) that make up a system. Internal energy
Define specific heat capacity The amount of energy needed to raise the temperature of 1 kg of a substance by 1 °C. Specific heat capacity
Substitute into ΔE = m c Δθ Calculate the change in thermal energy with m in kg, c in J/kg °C and Δθ in °C. Specific heat capacity
Know temperature stays constant during state changes While a substance melts, boils, freezes or condenses, its temperature does not change. Specific latent heat
Link gas temperature to molecules' kinetic energy The higher the temperature, the greater the average kinetic energy of the molecules, so the faster they move on average. Particle motion in gases
State the direction of gas pressure forces The pressure of a gas produces a net force at right angles to the wall of its container (or any surface). Pressure in gases
Give the relative charge of each particle Proton +1, neutron 0, electron −1, so the nucleus is positively charged. The structure of an atom
Recall the size of an atom The radius of an atom is about 1 × 10⁻¹⁰ m. The structure of an atom
State what mass number means The mass number is the total number of protons and neutrons in the nucleus. Mass number, atomic number and isotopes
Explain why atoms have no overall charge An atom has equal numbers of protons and electrons, and their charges are equal and opposite. Mass number, atomic number and isotopes
Describe the plum pudding model The atom is a ball of positive charge with negative electrons embedded in it. Development of the model of the atom
Define radioactive decay and activity Unstable nuclei give out radiation to become more stable; activity is decays per second, in becquerels (Bq). Radioactive decay and nuclear radiation
State what absorbs each radiation Alpha: paper; beta: a few mm of aluminium; gamma: reduced by thick lead or concrete. Radioactive decay and nuclear radiation
Recall the symbols for alpha and beta Alpha is \({}^{4}_{2}\mathrm{He}\) and beta is \({}^{0}_{-1}\mathrm{e}\). Nuclear equations
Define half-life The time for the number of unstable nuclei in a sample, or its count rate, to halve. Half-lives and random decay
Define contamination and irradiation Contamination: unwanted radioactive material on or in something; irradiation: exposure to radiation from outside. Radioactive contamination
Name natural sources of background radiation Rocks (including radon gas released from rocks) and cosmic rays from space. Background radiation
Name man-made sources of background radiation Fallout from nuclear weapons testing and from nuclear accidents. Background radiation
State that half-lives vary widely Half-lives range from fractions of a second to billions of years. Different half-lives of radioactive isotopes
Name two medical uses of nuclear radiation Exploring internal organs with tracers; destroying unwanted tissue such as tumours. Uses of nuclear radiation
Define nuclear fission The splitting of a large, unstable nucleus into two smaller nuclei. Nuclear fission
Name nuclear fuels used for fission Uranium (e.g. uranium-235) and plutonium (e.g. plutonium-239). Nuclear fission
Define nuclear fusion Two light nuclei join to form a heavier nucleus. Nuclear fusion
Sort common quantities into scalars and vectors Distance, speed, mass, time, energy and temperature are scalars; displacement, velocity, acceleration and force are vectors. Scalar and vector quantities
Name examples of non-contact forces Gravitational, electrostatic and magnetic forces act even when the objects are physically separated. Contact and non-contact forces
Calculate weight using W = m g For example, 60 kg × 9.8 N/kg = 588 N. Gravity
Find the resultant of forces along a line Add forces acting in the same direction; subtract forces acting in opposite directions. Resultant forces
Calculate work done using W = F s For example, 50 N × 3.0 m = 150 J. Work done and energy transfer
Distinguish elastic and inelastic deformation An elastically deformed object returns to its original shape when the forces are removed; an inelastically deformed one does not. Forces and elasticity
Calculate a moment using M = F d Moment (N m) = force (N) × perpendicular distance from the pivot (m). Moments, levers and gears
State that fluid pressure acts normal to surfaces The force caused by the pressure in a fluid acts at right angles to any surface. Pressure in a fluid (p = F/A)
Describe a simple model of the atmosphere The atmosphere is thin compared with the size of the Earth and gets less dense with increasing altitude. Atmospheric pressure
State that displacement is a vector Displacement is the straight-line distance from the start point to the finish point, with the direction of that line. Distance and displacement
Calculate distance using s = v t For example, 1.5 m/s for 60 s gives 90 m. Speed
Recall typical speeds of everyday motion Walking ~1.5 m/s, running ~3 m/s, cycling ~6 m/s, sound in air ~330 m/s. Speed
Explain the difference between speed and velocity Speed is a scalar (magnitude only); velocity is a vector (magnitude and direction). Velocity
Plot a distance–time graph from data Time on the x-axis, distance on the y-axis, labelled axes with units and sensible scales. Distance–time graphs
Calculate acceleration using a = Δv ÷ t From 4 m/s to 16 m/s in 3 s: a = 12 ÷ 3 = 4 m/s². Acceleration and velocity–time graphs
Describe motion from a velocity–time graph Horizontal line: constant velocity; sloping up: accelerating; sloping down: decelerating. Acceleration and velocity–time graphs
State Newton's First Law If the resultant force on an object is zero, it stays at rest or keeps moving at the same velocity. Newton's First Law
Find a force from steady motion At a steady speed in a straight line, the driving force equals the total resistive force. Newton's First Law
Calculate force using F = m a For example, 1200 kg × 2.5 m/s² = 3000 N. Newton's Second Law
State Newton's Third Law Whenever two objects interact, the forces they exert on each other are equal and opposite. Newton's Third Law
Calculate stopping distance from given data Add the thinking distance and the braking distance. Stopping distance
List factors that increase reaction time Tiredness, drugs, alcohol and distractions (e.g. using a phone). Reaction time
Explain how wet or icy roads affect braking There is less friction between the tyres and the road, so the braking distance is longer. Factors affecting braking distance
Describe the energy transfer when a vehicle brakes Energy is transferred from the kinetic store of the vehicle to the thermal store of the brakes. Braking forces and deceleration
State what waves transfer Waves transfer energy (and can carry information) from place to place, but they do not transfer matter. Transverse and longitudinal waves
Define frequency and period Frequency is the number of waves passing a point each second (Hz); the period is the time for one wave (s). Properties of waves
Calculate wave speed using v = f λ Multiply the frequency in Hz by the wavelength in m to get the wave speed in m/s. Properties of waves
State the law of reflection The angle of incidence equals the angle of reflection, both measured from the normal. Reflection of waves
Link spectrum position to wavelength and frequency Radio waves have the longest wavelength and lowest frequency; gamma rays have the shortest wavelength and highest frequency. Types of electromagnetic waves
State the effects of ultraviolet on skin Ultraviolet can make skin age prematurely and increases the risk of skin cancer. EM waves: production and hazards
Give two uses of microwaves Satellite communications and cooking food. Uses and applications of EM waves
Give three uses of infrared Electrical heaters, cooking food and infrared cameras. Uses and applications of EM waves
Define principal focus and focal length A convex lens brings parallel rays to a focus at the principal focus; the focal length is its distance from the lens. Lenses
State why an object looks a colour An opaque object reflects the wavelengths of its colour most strongly and absorbs the others. Visible light
Explain why objects look white or black White objects reflect all wavelengths equally; black objects absorb all wavelengths. Visible light
Link temperature to infrared emitted The hotter a body is, the more infrared radiation it radiates in a given time. Emission and absorption of infrared radiation
Identify magnetic forces as non-contact forces Magnets attract or repel each other without touching, so these are non-contact forces. Poles of a magnet
Draw the field pattern of a bar magnet Curved lines from the north pole to the south pole, with arrows, closest together at the poles. Magnetic fields
Describe how to show a wire's magnetic field Put plotting compasses around a vertical wire: they line up in a circle when the current is switched on. Electromagnetism
Describe how the Sun formed A nebula (a cloud of dust and gas) was pulled together by gravity until fusion started. Our solar system
State what decides a star's life cycle The size (mass) of the star decides which path it follows after the main sequence. The life cycle of a star
Describe the life cycle of a Sun-sized star Main sequence star, then red giant, then white dwarf, then black dwarf. The life cycle of a star
Tell apart planets, moons and artificial satellites Planets orbit a star, moons orbit planets, and artificial satellites are made and launched by people. Orbital motion and satellites
Describe what red-shift is Red-shift is an observed increase in the wavelength of light from most distant galaxies. Red-shift

Grade 5

Grade 5 checklist (PDF)

Describe energy changes in common situations Say which store decreases and which increases, e.g. a braking car: kinetic store down, thermal store of the brakes up. Energy stores and systems
Calculate kinetic energy Square the speed first, then multiply by the mass and by 0.5. Changes in energy
Calculate elastic potential energy of a spring Use E_e = ½ k e² with the extension in metres, as long as the limit of proportionality is not exceeded. Changes in energy
Calculate energy using ΔE = m c Δθ Find the temperature change first, then multiply mass × specific heat capacity × temperature change. Energy changes in systems
Compare the power of two machines If two motors do the same work, the one that takes less time has the greater power. Power
Explain how lubrication reduces wasted energy Oil reduces friction between moving parts, so less energy is dissipated by heating. Energy transfers in a system
Explain how insulation reduces energy transfer Thermal insulation lowers the rate of energy transfer by heating, e.g. loft insulation in a house. Energy transfers in a system
Give efficiency as a decimal or percentage Multiply the decimal by 100 to get a percentage; efficiency is never more than 1 (100%). Efficiency
Calculate efficiency from power values Divide the useful power output by the total power input. Efficiency
Explain why some resources are more reliable Wind, solar and waves depend on the weather (and solar on the time of day); fossil fuels and nuclear do not. National and global energy resources
Recognise thermistor and LDR symbols Both start from the resistor box: the thermistor has a line with a flat tail through it, the LDR has two arrows pointing in. Standard circuit diagram symbols
Place ammeters and voltmeters correctly Draw an ammeter in series with a component and a voltmeter in parallel across it. Standard circuit diagram symbols
State that current is the same around a loop In a single closed loop the current has the same value at every point. Electrical charge and current
Rearrange V = I R for I or R Use I = V ÷ R and R = V ÷ I, converting kΩ and mA first. Current, resistance and potential difference
Identify an ohmic conductor from its graph At constant temperature, current is directly proportional to pd, so the I–V graph is a straight line through the origin. Resistors
Describe how a diode controls current Current flows in one direction only; the diode has a very high resistance in the reverse direction. Resistors
Find a missing current or pd e.g. the supply pd equals the sum of the pds in series; the total current equals the sum of the branch currents. Series and parallel circuits
Explain the difference between dc and ac A direct pd acts in one direction only; an alternating pd keeps reversing direction. Direct and alternating potential difference
State the potential of each wire Live is about 230 V (compared with earth); neutral is at or close to 0 V; earth is at 0 V. Mains electricity
Rearrange P = V I Use I = P ÷ V, e.g. to find the current an appliance takes from the mains. Power
Calculate energy using E = Q V Charge in coulombs × pd in volts gives energy in joules. Energy transfers in everyday appliances
Explain charging using electron transfer Electrons move from one material to the other; the gainer becomes negative, the loser positive. Static charge
Describe evidence for forces between charges A charged rod hanging freely turns towards or away from another charged rod that is not touching it. Static charge
Describe how field strength changes with distance The field is strongest close to the charged object and weaker further away. Electric fields
Draw the field of a charged sphere Straight radial lines: arrows point outwards for a positive sphere and inwards for a negative sphere. Electric fields
Rearrange the density equation Use m = ρ × V to find a mass and V = m ÷ ρ to find a volume. Density of materials
Describe the density required practical Measure mass on a balance and find volume from measured dimensions or by displacement of water. Density of materials
Describe particle changes during melting and boiling Describe how the arrangement, spacing and motion of the particles change. Changes of state
Explain why a change of state is physical No new substance is made: if the change is reversed, the material recovers its original properties. Changes of state
State the two possible effects of heating Heating either raises the temperature of the system or produces a change of state. Internal energy
Link temperature to the particles' kinetic energy A higher temperature means the particles have a higher average kinetic energy: they move or vibrate faster. Internal energy
Work out the temperature change Δθ Δθ is the difference between the final and starting temperatures, not the final temperature. Specific heat capacity
Define specific latent heat The amount of energy needed to change the state of 1 kg of a substance with no change in temperature. Specific latent heat
Use E = m L Calculate the energy for a change of state with E in J, m in kg and L in J/kg. Specific latent heat
Find changes of state on heating graphs Flat sections show a change of state at the melting or boiling point; sloping sections show a temperature change. Specific latent heat
Explain how a gas exerts pressure Molecules collide with the walls of the container and exert a force on them; the force on each unit area is the pressure. Particle motion in gases
Describe how volume affects gas pressure At constant temperature, increasing the volume of a gas decreases its pressure, and decreasing the volume increases it. Pressure in gases
Compare the sizes of atom and nucleus The nucleus has a radius less than 1/10 000 of the atom's radius, yet contains almost all of its mass. The structure of an atom
Work out protons, neutrons and electrons Protons = atomic number; neutrons = mass number − atomic number; electrons = protons in a neutral atom. Mass number, atomic number and isotopes
Describe the nuclear model A tiny, positively charged nucleus containing most of the mass, with electrons around it. Development of the model of the atom
Compare plum pudding and nuclear models Charge and mass spread out, compared with concentrated in a nucleus with empty space around it. Development of the model of the atom
Describe what each radiation is Alpha: 2 protons and 2 neutrons; beta: a fast electron from the nucleus; gamma: electromagnetic radiation. Radioactive decay and nuclear radiation
State how alpha decay changes a nucleus The mass number falls by 4 and the atomic number falls by 2. Nuclear equations
State how beta decay changes a nucleus The mass number stays the same and the atomic number goes up by 1. Nuclear equations
Explain why gamma emission changes neither number Gamma is electromagnetic radiation with no mass and no charge. Nuclear equations
Explain what random decay means You cannot predict which nucleus will decay or when, but a large sample decays in a predictable way. Half-lives and random decay
Find a half-life from a graph Read the time for the activity or count rate to fall to half of any starting value. Half-lives and random decay
State that irradiation does not cause radioactivity An irradiated object does not become radioactive. Radioactive contamination
Correct a count rate for background Subtract the background count rate from the measured count rate. Background radiation
Link half-life to how fast activity falls A short half-life means the activity falls quickly; a long half-life means it falls slowly. Different half-lives of radioactive isotopes
Describe how a medical tracer is used A gamma emitter is swallowed or injected and detected outside the body by a gamma camera. Uses of nuclear radiation
Describe the products of fission Two smaller nuclei of similar size, two or three neutrons and gamma rays, all with kinetic energy. Nuclear fission
Compare a reactor with a nuclear weapon In a reactor the chain reaction is controlled; in a weapon it is uncontrolled, causing an explosion. Nuclear fission
State where fusion happens naturally In the cores of stars, e.g. hydrogen nuclei fuse to form helium in the Sun. Nuclear fusion
State where the energy comes from Some of the mass is converted into the energy of radiation. Nuclear fusion
Represent a vector with an arrow The length of the arrow shows the magnitude and the way it points shows the direction. Scalar and vector quantities
Identify the forces acting in a situation For example, a book on a table has its weight acting down and a normal contact force acting up. Contact and non-contact forces
Show forces as vector arrows Draw each arrow from the object, in the direction of the force, with its length showing the size. Contact and non-contact forces
Find mass or g from a weight m = W ÷ g and g = W ÷ m. Gravity
Describe how to measure weight Hang the object from a calibrated spring-balance (a newtonmeter). Gravity
Recognise balanced forces (zero resultant) If the resultant force is zero, the object stays at rest or keeps moving at a steady velocity. Resultant forces
Find force or distance from work done F = W ÷ s and s = W ÷ F. Work done and energy transfer
Convert between joules and newton-metres 1 J = 1 N m, so 250 N m of work is 250 J. Work done and energy transfer
Calculate force or extension with F = ke For example, k = 40 N/m and e = 0.15 m give F = 6.0 N. Forces and elasticity
Describe the spring extension required practical Hang known weights on a spring, measure its length each time, calculate the extension and plot force against extension. Forces and elasticity
Find a force or distance from a moment F = M ÷ d and d = M ÷ F. Moments, levers and gears
Calculate pressure using p = F ÷ A For example, 600 N on an area of 0.20 m² gives 3000 Pa. Pressure in a fluid (p = F/A)
Explain what causes atmospheric pressure Air molecules collide with a surface, and each collision exerts a force on it. Atmospheric pressure
Calculate distance and displacement along a line 40 m east then 15 m west: distance 55 m, displacement 25 m east. Distance and displacement
Explain why displacement can be zero After a round trip back to the start, the displacement is zero although the distance travelled is not. Distance and displacement
Find speed or time using s = vt v = s ÷ t and t = s ÷ v. Speed
Calculate average speed for a whole journey Average speed = total distance ÷ total time. Speed
Use + and − signs for velocity Along a line, e.g. +4 m/s to the right and −4 m/s to the left. Velocity
Calculate speed from the gradient Speed = change in distance ÷ change in time for a straight section. Distance–time graphs
Find acceleration from a velocity–time graph Acceleration = gradient = change in velocity ÷ time taken. Acceleration and velocity–time graphs
Explain steady motion using balanced forces A zero resultant force means there is no change in speed or direction. Newton's First Law
Find mass or acceleration using F = ma a = F ÷ m and m = F ÷ a. Newton's Second Law
Describe how acceleration depends on force and mass Acceleration is proportional to the resultant force and inversely proportional to the mass. Newton's Second Law
Identify Third Law partner forces If a boy pushes a wall with 150 N, the wall pushes the boy with 150 N in the opposite direction. Newton's Third Law
Calculate thinking distance using s = v t Thinking distance = speed × reaction time. Stopping distance
Calculate thinking distance from reaction time Thinking distance = speed × reaction time. Reaction time
Describe the ruler-drop reaction time test Catch a dropped ruler; the further it falls before you catch it, the longer your reaction time. Reaction time
Explain the effects of worn tyres and brakes Worn tyres grip the road less; worn brakes produce a smaller friction force. Factors affecting braking distance
Calculate the work done by a braking force W = F s, where s is the braking distance. Braking forces and deceleration
Link braking force to deceleration The greater the braking force, the greater the deceleration (F = m a). Braking forces and deceleration
Describe how transverse and longitudinal waves differ Compare the direction of the oscillations with the direction of energy transfer: perpendicular for transverse, parallel for longitudinal. Transverse and longitudinal waves
Identify compressions and rarefactions In a longitudinal wave, compressions are where the particles are close together and rarefactions are where they are spread out. Transverse and longitudinal waves
Use T = 1/f Find the period from the frequency, or the frequency from the period, e.g. f = 50 Hz gives T = 1 ÷ 50 = 0.02 s. Properties of waves
Draw a ray diagram for reflection Draw the normal at 90° to the surface, then the reflected ray at an equal angle on the other side, with arrows on both rays. Reflection of waves
State what happens to absorbed wave energy When a wave is absorbed, its energy is transferred to the material, usually heating it. Reflection of waves
State that all EM waves travel equally fast All EM waves travel at the same speed through a vacuum (space) or air: 3.0 × 10⁸ m/s. Types of electromagnetic waves
Give examples of EM waves transferring energy E.g. infrared from a fire warming your skin, or microwaves heating food in an oven. Types of electromagnetic waves
Draw a ray diagram for refraction Draw the normal; a ray that slows down (e.g. air into glass) bends towards the normal. EM waves: refraction and absorption
State which surfaces emit and absorb infrared best Matt black surfaces are the best emitters and absorbers of infrared; shiny silver surfaces are the worst. EM waves: refraction and absorption
State the effects of X-rays and gamma rays They are ionising radiation and can cause mutation of genes and cancer. EM waves: production and hazards
State where gamma rays come from Gamma rays come from changes in the nucleus of an atom. EM waves: production and hazards
Give uses of visible light and ultraviolet Visible light: fibre optic communications. Ultraviolet: energy-efficient lamps and sun tanning. Uses and applications of EM waves
Calculate magnification magnification = image height ÷ object height, with both heights in the same unit; it has no units. Lenses
Describe an image in three words Say whether it is real or virtual, upright or inverted, and magnified or diminished. Lenses
Describe specular and diffuse reflection Specular: from a smooth surface in a single direction. Diffuse: from a rough surface, scattered in many directions. Visible light
Explain how a colour filter works A filter transmits certain wavelengths (its own colour) and absorbs the others. Visible light
Identify good and poor emitters and absorbers Dark, matt surfaces are good emitters and absorbers; shiny surfaces are poor emitters and absorbers because they reflect radiation. Emission and absorption of infrared radiation
Describe how emission changes with temperature A hotter body emits more radiation at every wavelength, and relatively more at shorter wavelengths. Perfect black bodies and radiation
Describe the difference between permanent and induced magnets A permanent magnet produces its own magnetic field; an induced magnet only becomes a magnet when it is placed in a magnetic field. Poles of a magnet
Plot a magnetic field using a compass Mark where the compass needle points, move the compass on, repeat, then join the dots from N to S. Magnetic fields
State how field strength depends on distance The field is strongest at the poles and gets weaker further from the magnet. Magnetic fields
Draw the field around a straight wire Circles centred on the wire, further apart further out, with arrows showing the direction. Electromagnetism
State what affects the strength of the field The field is stronger for a bigger current, and weaker further from the wire. Electromagnetism
State how a star releases energy In the core of a main sequence star, hydrogen nuclei fuse to form helium, releasing energy. Our solar system
Describe the life cycle of a massive star Main sequence star, then red super giant, then supernova, then neutron star or black hole. The life cycle of a star
Give similarities between orbiting objects All are held in orbit by the gravity of a more massive object and move in (nearly) circular orbits. Orbital motion and satellites
Explain what red-shift shows about galaxies A red-shifted galaxy is moving away from us, and a bigger red-shift means it is further away and moving faster. Red-shift

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