AQA GCSE Physics: 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 what substances can do to EM waves A substance can absorb, transmit, refract or reflect EM waves. EM waves: refraction and absorption
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, force and momentum 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
State the range of human hearing Normal human hearing is from 20 Hz to 20 kHz (20 000 Hz). Sound waves
Define ultrasound Sound with a frequency higher than 20 kHz, the upper limit of human hearing. Waves for detection and exploration
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 what causes refraction Refraction happens because the wave changes speed when it enters a different substance. EM waves: refraction and absorption
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
State what the motor effect is A wire carrying a current in a magnetic field has a force on it, and so does the magnet. Fleming's left-hand rule
State that a coil carrying current rotates A coil of wire carrying a current in a magnetic field tends to rotate. Electric motors
Name the main parts of a loudspeaker A permanent magnet, a coil of wire in its magnetic field, and a cone attached to the coil. Loudspeakers
Name the parts of a moving-coil microphone A diaphragm attached to a coil, which sits in the magnetic field of a permanent magnet. Microphones
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
Define work as energy transferred by a force Work done = force × distance moved along the line of action of the force: W = F s. Increasing the pressure of a gas
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)
State that liquid pressure increases with depth The deeper a point is below the surface, the greater the pressure there. Pressure with depth and upthrust
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
Recall the momentum equation p = m v Momentum (kg m/s) = mass (kg) × velocity (m/s). Momentum of moving objects
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
Describe how sound makes solids vibrate Sound waves can travel through solids: a sound wave reaching a solid makes it vibrate, and the vibrations travel through it. Sound waves
Describe how the ear detects sound Sound waves make the eardrum vibrate; the vibrations are passed on to other parts of the ear, causing the sensation of sound. Sound waves
Give uses of ultrasound and echo sounding Medical scans (e.g. of a foetus), finding flaws inside metal, and measuring the depth of water. Waves for detection and exploration
Compare P-waves and S-waves P-waves are longitudinal and travel through solids and liquids; S-waves are transverse and cannot travel through liquids. Waves for detection and exploration
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
Recall the factors that affect the force The force is bigger for a stronger field (greater magnetic flux density), a bigger current and a longer length of wire in the field. Fleming's left-hand rule
Use Fleming's left-hand rule to find direction First finger = field (N to S), second finger = current (+ to −), thumb = force (motion). Fleming's left-hand rule
Explain why a current-carrying wire moves The magnetic field of the current interacts with the field of the magnet, producing a force on the wire. Fleming's left-hand rule
Explain why the coil's sides feel opposite forces The current is in opposite directions in the two sides, so the forces on them are in opposite directions. Electric motors
State that loudspeakers use the motor effect The coil carries a current in a magnetic field, so there is a force on it. Loudspeakers
State when a potential difference is induced When a conductor moves relative to a magnetic field, or the magnetic field around it changes. Induced potential
State when an induced current flows A current is only induced if the conductor is part of a complete circuit. Induced potential
State what an alternator and a dynamo produce An alternator generates alternating current (a.c.); a dynamo generates direct current (d.c.). Uses of the generator effect
Explain why a rotating coil induces a pd The sides of the coil move through (cut) the magnetic field lines, so a pd is induced. Uses of the generator effect
State that microphones use the generator effect Sound makes a coil move in a magnetic field, which induces a pd. Microphones
Describe the structure of a transformer A primary coil and a secondary coil wound on an iron core. Transformers
Identify step-up and step-down transformers Step-up: more turns on the secondary coil, so the output pd is bigger. Step-down: fewer turns on the secondary, so the output pd is smaller. Transformers
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

Grade 6

Grade 6 checklist (PDF)

Include wasted energy in your descriptions Say that friction or air resistance dissipates some energy to the thermal store of the surroundings. Energy stores and systems
Convert units before you substitute Change grams to kilograms, centimetres to metres and kilojoules to joules first. Changes in energy
Rearrange to find c, m or Δθ E.g. c = ΔE ÷ (m × Δθ) or Δθ = ΔE ÷ (m × c). Energy changes in systems
Describe the specific heat capacity practical Heat a metal block of known mass with an electric heater, measuring the energy supplied and the temperature rise. Energy changes in systems
Convert kW, kJ and minutes first Change kilowatts to watts, kilojoules to joules and minutes to seconds before you substitute. Power
Rearrange to find energy or time E = P × t and t = E ÷ P. Power
Link thermal conductivity to rate of transfer The higher the thermal conductivity, the higher the rate of energy transfer by conduction through a material. Energy transfers in a system
Describe how walls affect a building's cooling Thicker walls made of a material with a lower thermal conductivity make a building cool more slowly. Energy transfers in a system
Find the wasted or useful energy Wasted energy = total input − useful output, so useful output = total input − wasted energy. Efficiency
Describe the environmental impact of each resource E.g. burning fossil fuels releases carbon dioxide; hydro-electric dams flood valleys. National and global energy resources
Interpret circuit diagrams with junctions Work out which components are in series and which are on parallel branches. Standard circuit diagram symbols
Rearrange Q = I t and convert units Use I = Q ÷ t or t = Q ÷ I, converting minutes to seconds and mA to A first. Electrical charge and current
Describe the resistance of a wire practical Measure V and I for different lengths of wire and calculate R = V ÷ I each time. Current, resistance and potential difference
Explain the filament lamp I–V graph The line curves because the filament gets hotter as the current increases, so its resistance increases. Resistors
Describe the I–V characteristics practical Vary the pd with a variable resistor, record V and I, then reverse the connections for negative values. Resistors
Explain how added resistors change total resistance Series increases the total resistance; parallel decreases it. Series and parallel circuits
Interpret pd–time graphs for ac and dc A steady dc supply is a horizontal line; ac is a wave that goes positive and negative. Direct and alternating potential difference
Explain how the earth wire keeps you safe It stops the appliance becoming live and only carries a current if there is a fault. Mains electricity
Calculate power using P = I² R Square the current first, then multiply by the resistance. Power
Relate power ratings to energy transferred An appliance with a higher power rating transfers more energy each second. Energy transfers in everyday appliances
Explain why a high pd means low current For the same power, P = V I, so increasing the pd decreases the current. The National Grid
Explain why the two charges are equal The number of electrons gained by one material equals the number lost by the other. Static charge
Explain non-contact forces using fields Each charged object is in the other's electric field, so each experiences a force. Electric fields
Explain density differences between states using particles Gas particles are far apart, so each cubic metre of gas contains much less mass than a cubic metre of solid or liquid. Density of materials
Convert between g/cm³ and kg/m³ 1 g/cm³ = 1000 kg/m³, because 1 kg = 1000 g and 1 m³ = 1 000 000 cm³. Density of materials
Explain why density changes but mass does not The particles move closer together or further apart, so the volume changes but the number of particles does not. Changes of state
Explain mass changes in an open container Particles can escape into the air, so the container's mass drops even though the total mass is conserved. Changes of state
Explain how temperature differs from internal energy A large mass at a low temperature can have more internal energy than a small mass at a high temperature, because it has many more particles. Internal energy
Rearrange to find c, m or Δθ Use c = ΔE ÷ (m Δθ), m = ΔE ÷ (c Δθ) or Δθ = ΔE ÷ (m c). Specific heat capacity
Explain what affects a temperature rise The rise depends on the mass heated, the material (its specific heat capacity) and the energy supplied. Specific heat capacity
Distinguish latent heat of fusion and vaporisation Fusion: changing between solid and liquid. Vaporisation: changing between liquid and vapour (gas). Specific latent heat
Tell specific heat capacity from specific latent heat Specific heat capacity is for a temperature change with no change of state; specific latent heat is for a change of state with no temperature change. Specific latent heat
Explain pressure rise when heated at constant volume Faster molecules collide with the walls more often and with more force, so the pressure increases. Particle motion in gases
Explain the volume–pressure link using particles In a bigger volume, the molecules collide with the walls less often, so the pressure is lower. Pressure in gases
Use pV = constant for a fixed mass Use p₁V₁ = p₂V₂ to find a new pressure or volume. Pressure in gases
State how doing work affects a gas Doing work on a gas transfers energy to it, increasing its internal energy, which can raise its temperature. Increasing the pressure of a gas
Calculate the work done on a gas Use W = F s with the force on the piston in N and the distance it moves in m. Increasing the pressure of a gas
Explain how electrons change energy level Absorbing EM radiation moves an electron to a higher level, further out; emitting EM radiation moves it to a lower level, closer in. The structure of an atom
Compare sizes using standard form Divide the larger size by the smaller one, e.g. 1 × 10⁻¹⁰ m ÷ 1 × 10⁻¹⁴ m = 10 000. The structure of an atom
Define and identify isotopes Isotopes are atoms with the same number of protons but different numbers of neutrons. Mass number, atomic number and isotopes
Explain how an atom becomes a positive ion Losing one or more outer electrons leaves more protons than electrons, so the particle is positive. Mass number, atomic number and isotopes
Explain each alpha scattering observation Link 'straight through', 'deflected' and 'bounced back' to what each shows about the atom. Development of the model of the atom
Explain how a beta particle is formed A neutron in the nucleus turns into a proton, and a high-speed electron is ejected. Radioactive decay and nuclear radiation
Compare penetration, range and ionising power Alpha is the most ionising with the shortest range; gamma is the least ionising with the longest range. Radioactive decay and nuclear radiation
Complete a nuclear equation Make the mass numbers and the atomic numbers balance on both sides of the arrow. Nuclear equations
Calculate activity after whole half-lives Halve the activity once for each half-life that passes. Half-lives and random decay
Find a half-life from data Count the number of halvings in the time given, then divide the time by that number. Half-lives and random decay
Explain why findings are peer reviewed Published findings can be checked by other scientists, so the conclusions are more reliable. Radioactive contamination
Compare the hazards of contamination and irradiation Contamination keeps exposing you until it is removed or decays; irradiation stops when the source is removed. Radioactive contamination
Explain how job and location affect dose E.g. aircrew receive more cosmic rays; people in granite areas receive more radon. Background radiation
Explain the hazard of long half-lives The material stays radioactive for a very long time, so it needs safe long-term storage. Different half-lives of radioactive isotopes
Explain the hazard of short half-lives The material is hazardous for a short time, as its activity soon falls to a low level. Different half-lives of radioactive isotopes
Explain the choice of a tracer isotope Gamma, so it leaves the body and is weakly ionising; short half-life, so the dose is small. Uses of nuclear radiation
Describe how radiation destroys a tumour Gamma beams aimed at the tumour from several directions, or a source placed in or next to it. Uses of nuclear radiation
Explain how a chain reaction happens Neutrons released by one fission are absorbed by other nuclei, which also split. Nuclear fission
Draw or interpret a chain reaction diagram Show each fission releasing 2 or 3 neutrons that go on to cause more fissions. Nuclear fission
Complete a fusion equation Balance the mass numbers and atomic numbers, as for any nuclear equation. Nuclear fusion
Draw and read vector arrows to scale With a scale of 1 cm = 5 N, a 4.0 cm arrow represents a 20 N force. Scalar and vector quantities
Describe the forces between interacting objects Each object exerts a force on the other; the two forces are equal in size and opposite in direction. Contact and non-contact forces
Explain why weight changes but mass does not Weight depends on the gravitational field strength where the object is; mass is the amount of matter and stays the same. Gravity
State where the weight of an object acts The weight of an object can be treated as acting at a single point called its centre of mass. Gravity
Draw and use free body diagrams Show every force acting on one object as a labelled arrow drawn from the object. Resultant forces
Explain heating by work done against friction Work done against friction transfers energy to the thermal store, so the temperature of the object rises. Work done and energy transfer
Interpret linear and non-linear force–extension graphs A straight line through the origin shows F ∝ e with gradient k; the line curves beyond the limit of proportionality. Forces and elasticity
Apply balanced moments to a balanced object For a balanced object, total clockwise moment = total anticlockwise moment about the pivot. Moments, levers and gears
Find force or area from a pressure F = p × A and A = F ÷ p. Pressure in a fluid (p = F/A)
Calculate liquid pressure with p = hρg For example, 3.0 m × 1000 kg/m³ × 9.8 N/kg = 29 400 Pa. Pressure with depth and upthrust
Explain why pressure increases with depth At a greater depth there is a greater height, and so a greater weight, of liquid above that point. Pressure with depth and upthrust
State that atmospheric pressure decreases with height The higher you go, the lower the atmospheric pressure. Atmospheric pressure
Give displacement as magnitude and direction For example 25 m east, 300 m on a bearing of 045°, or −5 m along a line. Distance and displacement
Convert units of distance, time and speed km to m × 1000, minutes to seconds × 60, km/h to m/s ÷ 3.6. Speed
Explain when velocity changes Velocity changes if the speed changes, if the direction changes, or if both change. Velocity
Calculate average speed from a graph Read the total distance and total time, then divide. Distance–time graphs
Use the equation v² − u² = 2as It is on the equations sheet and applies to uniform acceleration; rearrange it for a, s, u or v. Acceleration and velocity–time graphs
Explain terminal velocity for a falling object It accelerates at first; drag increases with speed until the resultant force is zero. Acceleration and velocity–time graphs
Explain changing motion using resultant force Velocity (speed and/or direction) only changes if a resultant force acts. Newton's First Law
Use the resultant force in F = ma Find the resultant first, e.g. thrust minus drag, then divide by the mass. Newton's Second Law
Describe the acceleration required practical Vary the force (or the mass) on a trolley and measure its acceleration, e.g. with light gates. Newton's Second Law
Describe the features of a Third Law pair Same size, opposite directions, same type of force, acting on two different objects. Newton's Third Law
Explain motion using the Third Law A swimmer pushes water backwards; the water pushes the swimmer forwards. Newton's Third Law
Explain how speed affects stopping distance For a given braking force, a greater speed gives a greater thinking distance and a greater braking distance. Stopping distance
Evaluate reaction time measurements Identify anomalies, calculate means and suggest how to make a test fairer. Reaction time
Explain the effect of speed on braking distance A faster vehicle has more kinetic energy, so more work must be done to stop it. Factors affecting braking distance
Explain the safety implications of braking distances Lower speeds and bigger gaps are needed in bad conditions and near hazards. Factors affecting braking distance
Link speed to the braking force needed A faster vehicle needs a greater braking force to stop in the same distance. Braking forces and deceleration
Explain the dangers of large decelerations The brakes may overheat, and the vehicle may skid so the driver loses control. Braking forces and deceleration
Calculate momentum For example, 0.16 kg × 25 m/s = 4.0 kg m/s. Momentum of moving objects
Find mass or velocity using p = mv m = p ÷ v and v = p ÷ m. Momentum of moving objects
State the law of conservation of momentum In a closed system, the total momentum before an event equals the total momentum after it. Conservation of momentum
Calculate the total momentum of a system Add the momentum of each object, taking direction into account. Conservation of momentum
State that a force changes momentum When a force acts on an object that is moving, or able to move, its momentum changes. Changes in momentum
Calculate force from a change in momentum Force = change in momentum ÷ time taken; the equation is on the equations sheet. Changes in momentum
Describe evidence that the medium does not travel A floating object bobs up and down as ripples pass but does not move across the water with them. Transverse and longitudinal waves
Rearrange v = f λ with unit conversions Convert kHz, MHz, cm or mm to Hz and m first, then rearrange to find f or λ. Properties of waves
Describe measuring the speed of sound in air Time a sound over a long measured distance, then use speed = distance ÷ time. Properties of waves
Describe reflection, absorption and transmission for materials E.g. a mirror reflects most light, black card absorbs most light and clear glass transmits most light. Reflection of waves
Give examples of sound–vibration conversions E.g. the eardrum, a microphone's diaphragm, a loudspeaker cone, or a wall carrying sound into the next room. Sound waves
Use v = f λ for sound E.g. the wavelength of a 20 kHz sound in air (speed 340 m/s) is 340 ÷ 20 000 = 0.017 m. Sound waves
Calculate distance from an echo time Distance = speed × time, then halve it because the pulse travels there and back. Waves for detection and exploration
Use v = f λ with standard form E.g. find the wavelength of a 100 MHz radio wave using a speed of 3.0 × 10⁸ m/s. Types of electromagnetic waves
Describe the infrared radiation practical Fill a Leslie cube with hot water and measure the infrared from each face with a detector at the same distance. EM waves: refraction and absorption
Use radiation dose data to compare risks Compare doses in sieverts or millisieverts: the bigger the dose, the greater the risk of harm. EM waves: production and hazards
Draw a ray diagram for a convex lens Use a ray parallel to the axis that refracts through F, and a ray through the centre that goes straight on. Lenses
Distinguish transparent, translucent and opaque Transparent and translucent objects transmit light (translucent ones scatter it); opaque objects do not. Visible light
Explain everyday designs using emission and absorption E.g. solar water-heating panels are matt black so they absorb as much of the Sun's radiation as possible. Emission and absorption of infrared radiation
Define a perfect black body An object that absorbs all of the radiation incident on it, and does not reflect or transmit any. Emission and absorption of infrared radiation
Interpret intensity–wavelength graphs The hotter body's curve is higher and its peak is at a shorter wavelength. Perfect black bodies and radiation
Explain why induced magnetism always attracts The end of the material nearest the magnet becomes the opposite pole to the magnet's pole, so there is always attraction. Poles of a magnet
Define the direction of a magnetic field It is the direction of the force that would act on a north pole placed at that point. Magnetic fields
Compare field strength using field-line spacing Where the field lines are closer together, the field is stronger. Magnetic fields
Use the right-hand grip rule for field direction Point your right thumb along the current (+ to −); your curled fingers show the direction of the field. Electromagnetism
Draw the magnetic field of a solenoid Outside, like a bar magnet's field; inside, strong and uniform (straight, parallel, equally spaced lines). Electromagnetism
Calculate the force with F = BIl Substitute B in tesla, I in amperes and l in metres to get F in newtons. Fleming's left-hand rule
Describe how to reverse or speed up motors Reverse the current or the field to reverse it; increase the current, field strength or number of turns to speed it up. Electric motors
Find which way a motor coil turns Use Fleming's left-hand rule on each side of the coil to find the forces, then decide clockwise or anticlockwise. Electric motors
Explain why the cone vibrates The current alternates, so the force on the coil keeps reversing, pushing the coil and cone back and forth. Loudspeakers
Explain how the vibrating cone produces sound The cone pushes and pulls on the air, making pressure variations (compressions and rarefactions) that travel as a sound wave. Loudspeakers
Recall what affects the size of induced pd Faster movement (faster change of field), a stronger magnetic field and more turns on the coil all increase it. Induced potential
Recall what affects the direction of induced pd Reversing the direction of movement, or reversing the magnetic field, reverses it. Induced potential
Describe the job of slip rings Each end of the coil stays connected to the same brush, so the output pd alternates as the coil turns. Uses of the generator effect
Explain how sound makes the coil move The pressure variations of the sound wave make the diaphragm, and the coil attached to it, vibrate. Microphones
Use the turns-ratio equation Substitute into V_p / V_s = n_p / n_s and rearrange to find a pd or a number of turns. Transformers
Explain why the core is made of iron Iron is easily magnetised, so it carries the changing magnetic field through the secondary coil. Transformers
Explain why a main sequence star is stable The inward pull of gravity is balanced by the outward expansion caused by the energy released by fusion. Our solar system
Explain how stars make new elements Hydrogen fuses into helium, then heavier elements up to iron form, and elements heavier than iron form in supernovae. The life cycle of a star
Calculate orbital speed from radius and time Use speed = distance ÷ time, where the distance for one orbit is 2 × π × radius. Orbital motion and satellites
Describe the Big Bang theory The universe began from a very small region that was extremely hot and dense. Red-shift
Use galaxy data to describe a relationship The speed a galaxy moves away is roughly directly proportional to its distance, so you can use this to make predictions. Red-shift

Grade 7

Grade 7 checklist (PDF)

Use calculations to compare energy stores Calculate the energy in each store before and after a change to show how the total energy is shared out. Energy stores and systems
Rearrange to find speed, height or extension E.g. h = E_p ÷ (m × g), or v = √(2E_k ÷ m), taking the square root last. Changes in energy
Explain why the measured value is too high Energy is dissipated to the surroundings, so more energy is supplied than the block gains. Energy changes in systems
Combine power with work done or energy Find the work done or gravitational potential energy gained first, then divide by the time. Power
Plan the thermal insulation practical Compare how fast hot water cools when wrapped in different materials, keeping the other variables the same. Energy transfers in a system
Rearrange to find the input or output Useful output = efficiency × total input; total input = useful output ÷ efficiency. Efficiency
Describe ways to increase efficiency Reduce the wasted transfers, e.g. lubricate moving parts, streamline, insulate (Higher tier only). Efficiency
Explain trends in energy resource use Use data and reasons such as cutting carbon dioxide emissions and the falling cost of renewables. National and global energy resources
Analyse resistance against length results A straight line through the origin shows resistance is directly proportional to length. Current, resistance and potential difference
Find resistance at a point on I–V graph Read V and I at that point and use R = V ÷ I, not the gradient. Resistors
Explain thermistor and LDR sensing circuits Link a change in temperature or light to a change in resistance, current and the pd across each component. Resistors
Solve multi-step series circuit problems Find the total resistance, then I = V ÷ R, then the pd across each resistor with V = I R. Series and parallel circuits
Find frequency from a pd–time graph Read the time for one complete cycle and use frequency = 1 ÷ time period. Direct and alternating potential difference
Explain why touching the live wire is dangerous Your body is at 0 V, so there is a large pd across you and a current flows through you. Mains electricity
Explain dangers even when a switch is open The live wire is still connected to the supply, so it is still at about 230 V. Mains electricity
Find current or resistance from P = I² R Use I = √(P ÷ R) or R = P ÷ I². Power
Combine E = Q V with Q = I t Find the charge first, then the energy, in multi-step problems. Energy transfers in everyday appliances
Explain why the National Grid is efficient A lower current means less heating of the cables, so less energy is wasted. The National Grid
Describe how a spark is produced Charge builds up until the pd is large enough for charge to jump through the air to a nearby earthed conductor. Static charge
Explain how the force changes with distance Closer objects are in a stronger part of each other's field, so the force is bigger. Electric fields
Solve multi-step density problems For example, find a volume from dimensions in cm, convert it to m³, then use a density in kg/m³ to find the mass. Density of materials
Explain energy changes during a change of state The energy supplied increases the potential energy of the particles, so internal energy rises but the temperature does not. Internal energy
Use heater power and time in calculations Find the energy supplied with E = P t, then use it in ΔE = m c Δθ. Specific heat capacity
Explain why a measured c is too high Energy is transferred to the surroundings, so the temperature rise is smaller and c = ΔE ÷ (m Δθ) comes out larger. Specific heat capacity
Do multi-step heating and melting calculations Work out each stage separately with ΔE = m c Δθ or E = m L, then add the energies. Specific latent heat
Apply the particle model to real situations For example, explain why a sealed can may burst if heated, or why tyre pressure falls on a cold night. Particle motion in gases
Test data against pV = constant Multiply p × V for each result: if the products are the same, the data fit pV = constant. Pressure in gases
Interpret graphs of pressure against volume p against V is a curve (inverse proportion); p against 1/V is a straight line through the origin. Pressure in gases
Explain why a bicycle pump gets warm Work done on the air increases its internal energy, so the average kinetic energy of the molecules and the temperature rise. Increasing the pressure of a gas
Identify isotopes and ions from data Use particle numbers in a table to decide which atoms are isotopes of the same element and which particles are charged. Mass number, atomic number and isotopes
Explain why the plum pudding model was replaced It predicted only tiny deflections, so large deflections needed a new model with a concentrated, charged nucleus. Development of the model of the atom
Explain how new evidence changes models When experiments give results a model cannot explain, scientists change or replace the model. Development of the model of the atom
Choose the best radiation for a use Justify the choice using penetration and ionising power, and say why the others are unsuitable. Radioactive decay and nuclear radiation
Identify the decay type from an equation Compare the mass and atomic numbers before and after to see what was emitted. Nuclear equations
Correct count rates for background radiation Subtract the background count rate from each reading before finding the half-life. Half-lives and random decay
Explain which radiation is most hazardous where Outside the body beta and gamma are more hazardous; inside the body alpha is most hazardous. Radioactive contamination
Convert and compare doses in sieverts Use 1 Sv = 1000 mSv to compare doses given as data. Background radiation
Choose an isotope with a suitable half-life E.g. a few hours for a medical tracer; years for a smoke alarm or thickness gauge. Different half-lives of radioactive isotopes
Explain why beams come from several directions The tumour gets a large dose while each part of the healthy tissue gets a much smaller dose. Uses of nuclear radiation
Explain how a reactor controls fission Control rods absorb neutrons so that, on average, one neutron from each fission causes another. Nuclear fission
Explain why fusion needs extreme conditions Very high temperatures and pressures let positive nuclei overcome their repulsion and get close enough to fuse. Nuclear fusion
Explain scalar–vector pairs such as speed and velocity Two objects can have the same speed but different velocities if they move in different directions. Scalar and vector quantities
Use the proportionality between weight and mass W ∝ m, so a graph of weight against mass is a straight line through the origin with a gradient equal to g. Gravity
Find a resultant using a scale drawing Draw the two forces tip-to-tail to scale; the resultant is the arrow from the start of the first to the end of the second. Resultant forces
Link work done to changes in energy stores Work done by brakes equals the kinetic energy lost; work done lifting an object equals its gain in gravitational potential energy. Work done and energy transfer
Calculate elastic potential energy stored Use E_e = 0.5 × k × e², up to the limit of proportionality. Forces and elasticity
Link work done to energy stored If the spring is not inelastically deformed, the work done stretching it equals the elastic potential energy stored. Forces and elasticity
Explain how levers act as force multipliers A small effort far from the pivot gives the same moment as a large load close to the pivot. Moments, levers and gears
Explain how gears change speed and moment A small gear driving a larger gear makes it turn more slowly but with a larger moment. Moments, levers and gears
Convert areas and pressures to SI units 1 m² = 10 000 cm², so divide cm² by 10 000; 1 kPa = 1000 Pa. Pressure in a fluid (p = F/A)
Explain how area affects pressure and force The same force on a smaller area gives a greater pressure; the same pressure on a larger area gives a greater force. Pressure in a fluid (p = F/A)
Explain what causes upthrust The pressure on the bottom surface of a submerged object is greater than on its top surface, giving a resultant upward force. Pressure with depth and upthrust
Explain floating and sinking using forces An object floats when the upthrust equals its weight; it sinks if its weight is greater than the upthrust when fully submerged. Pressure with depth and upthrust
Explain why pressure decreases with altitude There are fewer air molecules, and so a smaller weight of air, above a surface the higher it is. Atmospheric pressure
Calculate forces due to atmospheric pressure Use F = p × A, e.g. 100 000 Pa on 0.50 m² gives 50 000 N. Atmospheric pressure
Find the displacement for a right-angled journey Use a scale drawing (or Pythagoras): 30 m north then 40 m east is 50 m at about 53° east of north. Distance and displacement
Estimate speeds, distances and times For example, walking 1 km at ~1.5 m/s takes about 670 s, roughly 11 minutes. Speed
Explain circular motion: constant speed, changing velocity The direction of motion changes all the time, so the velocity changes even though the speed stays the same. Velocity
Recognise acceleration and deceleration on the graph A curve getting steeper shows acceleration; a curve getting less steep shows deceleration. Distance–time graphs
Estimate the size of everyday accelerations For example, a car reaching 30 m/s in about 10 s accelerates at about 3 m/s². Acceleration and velocity–time graphs
Find distance from area under v–t graph Split the area into rectangles and triangles and add them. Acceleration and velocity–time graphs
Define and use the idea of inertia Inertia is the tendency of objects to continue in their state of rest or of uniform motion. Newton's First Law
Estimate forces in everyday road transport For example, a car of mass ~1000 kg decelerating at ~6 m/s² needs ~6000 N. Newton's Second Law
Distinguish Third Law pairs from balanced forces Balanced forces act on the same object; a Third Law pair acts on two different objects. Newton's Third Law
Apply the Third Law to equilibrium situations A book on a table pushes down on the table, and the table pushes up on the book with an equal force. Newton's Third Law
Interpret stopping distance data and graphs Thinking distance rises in proportion to speed; braking distance rises more and more steeply. Stopping distance
Evaluate factors affecting thinking distance from data Compare thinking distances with and without a factor, at the same speed. Reaction time
Estimate stopping distances at typical speeds A car on a dry road needs roughly 25 m to stop from 13 m/s and roughly 100 m from 31 m/s. Factors affecting braking distance
Calculate a braking force from kinetic energy Braking force × braking distance = ½ m v². Braking forces and deceleration
Explain that momentum is a vector Momentum has the same direction as the velocity; opposite directions have opposite signs. Momentum of moving objects
Compare the momentum of different objects A slow, heavy object can have more momentum than a fast, light one. Momentum of moving objects
Calculate the velocity after objects join Total momentum before = (m₁ + m₂) × v after. Conservation of momentum
Explain explosions and recoil using momentum The total momentum is zero before, so the parts move apart with equal and opposite momentum. Conservation of momentum
Explain what a closed system is No external forces act on the system, so its total momentum cannot change. Conservation of momentum
Derive the rate-of-change-of-momentum equation Substitute a = Δv ÷ Δt into F = m a to get F = m Δv ÷ Δt. Changes in momentum
Explain how safety features reduce injury They increase the time taken for the momentum to change, so the force is smaller. Changes in momentum
Explain how particles move in a sound wave Air particles vibrate backwards and forwards about fixed positions, parallel to the direction of travel, passing energy on to their neighbours. Transverse and longitudinal waves
Describe the ripple tank and string practical Measure across several wavelengths, find the frequency, use v = f λ, and explain why the apparatus suits each measurement. Properties of waves
Explain how sound changes in a new medium The frequency stays the same, so if the speed increases the wavelength increases in proportion (λ = v ÷ f). Properties of waves
Describe the reflection and refraction practical Use a ray box, a mirror or glass block, paper and a protractor to measure angles for several angles of incidence. Reflection of waves
Explain how to make the angles accurate Use a narrow ray in a darkened room, mark the ray with crosses far apart, and measure every angle from the normal. Reflection of waves
Explain why hearing has a limited range The conversion of sound waves into vibrations of the eardrum and other parts of the ear only works over a limited frequency range. Sound waves
Explain how ultrasound produces an image Pulses are partially reflected at each boundary between media, and the echo times give the distance to each boundary. Waves for detection and exploration
Explain why higher frequency means shorter wavelength All EM waves have the same speed, so a higher frequency means a proportionally shorter wavelength. Types of electromagnetic waves
Explain refraction using wave fronts (HT) The part of a wave front that reaches the slower medium first slows down first, so the wave front changes direction. EM waves: refraction and absorption
Explain how radio waves are produced (HT) Oscillations (an alternating current) in an electrical circuit produce radio waves of the same frequency. EM waves: production and hazards
Explain why microwaves suit satellite communications (HT) Microwaves pass through the Earth's atmosphere, so they can reach satellites in space. Uses and applications of EM waves
Explain why X-rays suit imaging bones (HT) X-rays pass through soft tissue but are absorbed by bone, so bones show up on the image. Uses and applications of EM waves
Explain real and virtual images A real image forms where rays actually meet and can be shown on a screen; a virtual image is where rays only appear to come from. Lenses
Draw a ray diagram for a concave lens The parallel ray spreads out as if it came from F on the object's side; the image is always virtual. Lenses
Predict colours seen through filters E.g. a blue object seen through a red filter looks black, because no light from it gets through. Visible light
Explain why a black body emits best A good absorber is also a good emitter, so a perfect absorber would be the best possible emitter. Emission and absorption of infrared radiation
Explain constant temperature using absorption and emission (HT) A body at constant temperature absorbs radiation at the same rate as it emits radiation. Perfect black bodies and radiation
Explain why a body warms or cools (HT) It warms up if it absorbs radiation faster than it emits it, and cools down if it emits faster than it absorbs. Perfect black bodies and radiation
Explain how to test for a magnet Only repulsion proves an object is a permanent magnet, because a magnetic material is attracted to both poles. Poles of a magnet
Explain the compass evidence for Earth's magnetic core A compass lines up in a fixed direction even far from any magnet, so the Earth must have a magnetic field, which comes from its core. Magnetic fields
Explain how solenoids and iron cores strengthen fields The fields of all the turns add together inside the coil, and an iron core becomes magnetised, making the field much stronger. Electromagnetism
Explain how an electromagnetic device works e.g. in a relay, a small current magnetises an electromagnet, which attracts an iron armature and closes the contacts of a second circuit. Electromagnetism
Rearrange F = BIl after converting units e.g. find B in tesla when the length is given in mm or cm. Fleming's left-hand rule
Explain the role of the split-ring commutator It reverses the current in the coil every half turn, so the coil keeps turning in the same direction. Electric motors
Link the frequency of the current to pitch The cone vibrates at the same frequency as the current, so the sound has that frequency. Loudspeakers
Link the size of the current to loudness A bigger current gives a bigger force, so the cone vibrates with a bigger amplitude and the sound is louder. Loudspeakers
Explain why a still magnet induces nothing With no relative movement the field through the coil does not change, so no pd is induced. Induced potential
Describe the job of a dynamo's commutator It swaps the connections every half turn, so the output pd is always in the same direction. Uses of the generator effect
Sketch pd–time graphs for both generators Alternator: a wave going above and below zero. Dynamo: humps that are all on the same side of zero. Uses of the generator effect
Explain how an alternating current is produced The coil moves back and forth in the field, so the induced pd keeps changing direction. Microphones
Link frequency and loudness to the current The current has the same frequency as the sound; a louder sound gives a bigger current. Microphones
Explain how a transformer works Alternating current in the primary → changing magnetic field in the core → alternating pd induced in the secondary. Transformers
Use the transformer power equation For a 100% efficient transformer, find the current drawn from the supply for a given power output. Transformers
Explain how gravitational collapse starts fusion As the cloud collapses its particles gain kinetic energy, so the core heats up until nuclei move fast enough to fuse. Our solar system
Explain how elements from stars reach planets A supernova scatters elements through the universe, and new stars and planets form from clouds containing them. The life cycle of a star
Compare two life cycles in a 6-mark answer Give both paths in order, compare them stage by stage and include the processes at each stage. The life cycle of a star
Explain changing velocity at constant speed (HT) Gravity acts at right angles to the motion, so it changes the direction, and so the velocity, but not the speed. Orbital motion and satellites
Explain red-shift as evidence for expansion More distant galaxies move away faster, which shows that space itself is expanding and supports the Big Bang theory. Red-shift

Grade 8

Grade 8 checklist (PDF)

Link energy stores in multi-step problems Use 'energy lost from one store = energy gained by another' to find a speed or a height. Changes in energy
Find c from a temperature–time graph With a heater of constant power P, the gradient is P ÷ (m × c), so c = P ÷ (m × gradient). Energy changes in systems
Evaluate energy resources using data Weigh up reliability, cost and environmental impact, then give a conclusion with a reason. National and global energy resources
Solve parallel problems using branch currents Each branch has the full supply pd; find each branch current with I = V ÷ R and add them. Series and parallel circuits
Combine power equations with V = I R Link P = V I, P = I² R and V = I R in multi-step problems. Power
Calculate power wasted in transmission cables Find the current with I = P ÷ V, then the heating loss with P = I² R. The National Grid
Explain sparking using electric fields A very strong field ionises the air, so charge can flow through the air as a spark. Electric fields
Find specific latent heat from experimental data Use E = P t for the energy supplied and the mass that changed state, then L = E ÷ m. Specific latent heat
Explain when pV = constant does not apply It only works for a fixed mass of gas at constant temperature; if the gas heats up or leaks, the prediction is wrong. Pressure in gases
Explain why fast compression heats more There is less time for energy to be transferred away by heating, so more of the work done stays in the gas as internal energy. Increasing the pressure of a gas
Explain why pressure rises more than pV predicts The temperature rises as well, so the molecules hit the walls more often and harder than they would at constant temperature. Increasing the pressure of a gas
Link ionising power to range The more strongly a radiation ionises, the faster it loses energy, so the shorter its range. Radioactive decay and nuclear radiation
Work through a chain of decays Apply several alpha and beta decays in turn to find the final nucleus. Nuclear equations
Find the net decline as a ratio After n half-lives, (1/2)ⁿ of the original remains, so the net decline is the rest (Higher tier). Half-lives and random decay
Compare activities of samples with different half-lives For the same number of nuclei, the isotope with the shorter half-life has the higher activity. Different half-lives of radioactive isotopes
Evaluate risks and benefits using data Compare the dose and its risk with the benefit of diagnosis or treatment, and reach a conclusion. Uses of nuclear radiation
Compare fission and fusion in detail Compare what happens, the nuclei involved, the conditions needed and where each is used. Nuclear fusion
Resolve a force into two perpendicular components Draw the force to scale and complete a right-angled triangle to measure its horizontal and vertical components. Resultant forces
Use vector diagrams for equilibrium If three forces are in equilibrium, their arrows drawn tip-to-tail form a closed triangle. Resultant forces
Solve moment problems with several forces Add up all the clockwise moments and all the anticlockwise moments, then set the totals equal. Moments, levers and gears
Use density to predict floating or sinking An object less dense than the liquid floats; an object denser than the liquid sinks. Pressure with depth and upthrust
Calculate the pressure difference between two depths Pressure difference = difference in depth × ρ × g. Pressure with depth and upthrust
Explain effects of pressure differences A resultant force acts from the higher-pressure side towards the lower-pressure side, e.g. a sealed bottle being squashed. Atmospheric pressure
Link changing velocity to acceleration and force A changing velocity is an acceleration, so there must be a resultant force on the object. Velocity
Find speed at an instant using a tangent Draw a tangent to the curve at that time and calculate its gradient. Distance–time graphs
Count squares to find area under curves Count the squares under a curved line and multiply by the distance one square represents. Acceleration and velocity–time graphs
Explain inertial mass Inertial mass is a measure of how difficult it is to change an object's velocity: force ÷ acceleration. Newton's Second Law
Explain why braking distance increases fastest For the same braking force, braking distance is proportional to speed squared, because kinetic energy is. Stopping distance
Calculate a reaction time from ruler-drop distance Use v² − u² = 2 a s with a = 9.8 m/s² to find v, then t = v ÷ a. Reaction time
Explain why braking distance depends on speed squared Braking force × braking distance = ½ m v², so for a constant force, distance ∝ v². Factors affecting braking distance
Estimate braking forces for typical road vehicles Use typical masses and speeds with F = m a or work done = kinetic energy. Braking forces and deceleration
Calculate a change in momentum, including direction For a rebound, change in momentum = m v − m u with the correct signs. Momentum of moving objects
Solve collisions with objects moving in opposite directions Use + and − for direction; the sign of the answer gives the direction of motion. Conservation of momentum
Rearrange to find a time or velocity change Δt = m Δv ÷ F and Δv = F Δt ÷ m. Changes in momentum
Compare forces for different stopping times The same change in momentum over a longer time gives a proportionally smaller force. Changes in momentum
Explain seismic evidence for a liquid outer core S-waves are not detected on the far side of the Earth from an earthquake, so part of the core must be liquid. Waves for detection and exploration
Explain how radio waves are received (HT) Radio waves absorbed by an aerial can induce an alternating current with the same frequency as the waves. EM waves: production and hazards
Explain why gamma rays treat cancer (HT) Gamma rays are ionising and carry a lot of energy, so a carefully aimed beam can kill cancer cells. Uses and applications of EM waves
Predict the image for any object position E.g. an object closer to a convex lens than F gives a virtual, upright, magnified image. Lenses
Explain colours using absorption, transmission and reflection Follow the light from source to object to filter to eye, saying which wavelengths are reflected, absorbed or transmitted at each stage. Visible light
Explain what controls the Earth's temperature (HT) The rates of absorption and emission of radiation, and how much radiation is reflected into space. Perfect black bodies and radiation
Predict how changes affect the force e.g. reversing both the current and the field leaves the direction unchanged; doubling I and halving l leaves F unchanged. Fleming's left-hand rule
Explain why the coil keeps turning past vertical When the coil is vertical the forces give no turning effect, but its momentum carries it past, just as the commutator reverses the current. Electric motors
Contrast a loudspeaker with a microphone They have the same parts, but a loudspeaker uses the motor effect (current → movement) and a microphone uses the generator effect (movement → current). Loudspeakers
Explain how the induced current opposes the change The induced current makes a magnetic field that opposes the movement, e.g. the coil repels a magnet being pushed in. Induced potential
Predict graph changes for faster rotation Faster rotation gives a higher peak pd and a shorter time for each cycle (a higher frequency). Uses of the generator effect
Compare a microphone with a loudspeaker Both have a coil in a magnet's field; a microphone uses the generator effect and a loudspeaker the motor effect. Microphones
Explain why high-pd transmission is efficient For the same power, a higher pd means a smaller current, so less energy is wasted heating the cables. Transformers
Link orbital speed and orbit radius (HT) A stable orbit with a smaller radius needs a higher speed, so if the speed changes the radius must change. Orbital motion and satellites
Explain what is not yet understood Since 1998, galaxies have been observed receding ever faster, and dark mass and dark energy are still not understood. Red-shift

Grade 9

Grade 9 checklist (PDF)

Explain how P-waves reveal the core's size P-waves change speed and refract at the core boundary, leaving a P-wave shadow zone whose position shows the size of the core. Waves for detection and exploration
Interpret diagrams of the Earth's radiation balance (HT) Use given data or diagrams to explain changes in the temperature of the Earth's surface and atmosphere. Perfect black bodies and radiation
Apply the generator effect to new situations e.g. describe and explain the pd recorded as a magnet falls right through a coil. Induced potential
Link the coil's position to the induced pd The pd is biggest when the plane of the coil is parallel to the field and zero when it is at right angles to the field. Uses of the generator effect
Combine both transformer equations in one problem e.g. find the secondary pd from the turns ratio, then the secondary current from the power. Transformers

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