AQA Level 1/Level 2 GCSE (9-1) in Physics

v ² − u ² = 2 a s

Students should be able to estimate the magnitude of everyday accelerations.

The acceleration of an object can be calculated from the gradient of a velocity–time graph.

An object falling through a fluid initially accelerates due to the force of gravity.

The following equation applies to uniform acceleration:

final velocity ² − initial velocity ² = 2 × acceleration × distance

final velocity, v, in metres per second, m/s

acceleration = change in velocity / time taken

acceleration, a, in metres per second squared, m/s²

a = Δv / t

(HT only) interpret enclosed areas in velocity–time graphs to determine distance travelled (or displacement).

(HT only) measure, when appropriate, the area under a velocity–time graph by counting squares.

(HT only) The distance travelled by an object (or displacement of an object) can be calculated from the area under a velocity–time graph.

Eventually the resultant force will be zero and the object will move at its terminal velocity.

(Physics only) Students should be able to: draw and interpret velocity–time graphs for objects that reach terminal velocity interpret the changing motion in terms of the forces acting.

distance, s, in metres, m

initial velocity, u, in metres per second, m/s

Near the Earth’s surface any object falling freely under gravity has an acceleration of about 9.8 m/s².

The average acceleration of an object can be calculated using the equation:

time, t, in seconds, s

Students should be able to recall and apply this equation.

change in velocity, Δv, in metres per second, m/s

Students should be able to draw velocity–time graphs from measurements and interpret lines and slopes to determine acceleration.

The atmosphere is a thin layer (relative to the size of the Earth) of air round the Earth. The atmosphere gets less dense with increasing altitude.

Air molecules colliding with a surface create atmospheric pressure.

So as height increases there is always less air above a surface than there is at a lower height.

The number of air molecules (and so the weight of air) above a surface decreases as the height of the surface above ground level increases.

So atmospheric pressure decreases with an increase in height.

Students should be able to: describe a simple model of the Earth’s atmosphere and of atmospheric pressure explain why atmospheric pressure varies with height above a surface.

Background radiation is around us all of the time. It comes from: natural sources such as rocks and cosmic rays from space man-made sources such as the fallout from nuclear weapons testing and nuclear accidents.

The level of background radiation and radiation dose may be affected by occupation and/or location.

Radiation dose is measured in sieverts (Sv) 1000 millisieverts (mSv) = 1 sievert (Sv) Students will not need to recall the unit of radiation dose.

height, h, in metres, m

Students should be able to calculate the amount of energy associated with a moving object, a stretched spring and an object raised above ground level.

Students should be able to apply equations relating force, mass, velocity and acceleration to explain how the changes involved are inter-related.

Students should be able to explain safety features such as: air bags, seat belts, gymnasium crash mats, cycle helmets and cushioned surfaces for playgrounds with reference to the concept of rate of change of momentum.

When a force acts on an object that is moving, or able to move, a change in momentum occurs.

Students should be able to describe how, when substances change state (melt, freeze, boil, evaporate, condense or sublimate), mass is conserved.

Changes of state are physical changes which differ from chemical changes because the material recovers its original properties if the change is reversed.

Students should be able to distinguish between specific heat capacity and specific latent heat.

If a change of state happens: The energy needed for a substance to change state is called latent heat. When a change of state occurs, the energy supplied changes the energy stored (internal energy) but not the temperature.

The specific latent heat of a substance is the amount of energy required to change the state of one kilogram of the substance with no change in temperature.

energy f or a change o f state = mass × speci f ic latent heat E = m L energy, E, in joules, J mass, m, in kilograms, kg specific latent heat, L, in joules per kilogram, J/kg Specific latent heat of fusion – change of state from solid to liquid Specific latent heat of vaporisation – change of state from liquid to vapour Students should be able to interpret heating and cooling graphs that include changes of state.

In a closed system, the total momentum before an event is equal to the total momentum after the event.

Students should be able to use the concept of momentum as a model to: describe and explain examples of momentum in an event, such as a collision (physics only) complete calculations involving an event, such as the collision of two objects.

This is called conservation of momentum.

Examples of contact forces include friction, air resistance, tension and normal contact force.

A force is a push or pull that acts on an object due to the interaction with another object. All forces between objects are either: contact forces – the objects are physically touching non-contact forces – the objects are physically separated.

Students should be able to describe the interaction between pairs of objects which produce a force on each object. The forces to be represented as vectors.

Force is a vector quantity.

Examples of non-contact forces are gravitational force, electrostatic force and magnetic force.

The greater the resistance of the component the smaller the current for a given potential difference (pd) across the component.

Current, potential difference or resistance can be calculated using the equation: potential di f f erence = current × resistance V = I R potential difference, V, in volts, V current, I, in amperes, A (amp is acceptable for ampere) resistance, R, in ohms, Ω Required practical activity 3: Use circuit diagrams to set up and check appropriate circuits to investigate the factors affecting the resistance of electrical circuits. This should include: the length of a wire at constant temperature combinations of resistors in series and parallel.

The current (I) through a component depends on both the resistance (R) of the component and the potential difference (V) across the component.

Questions will be set using the term potential difference. Students will gain credit for the correct use of either potential difference or voltage.

Required practical activity 5: use appropriate apparatus to make and record the measurements needed to determine the densities of regular and irregular solid objects and liquids. Volume shoul be determined from the dimensions of regularly shaped objects, and by a displacement technique for irregularly shaped objects. Dimensions to be measured using appropriate apparatus such as a ruler, micrometer or Vernier callipers.

Students should be able to recognise/draw simple diagrams to model the difference between solids, liquids and gases.

Students should be able to explain the differences in density between the different states of matter in terms of the arrangement of atoms or molecules.

Radioactive isotopes have a very wide range of half-life values.

Students should be able to explain why the hazards associated with radioactive material differ according to the half-life involved.

Mains electricity is an ac supply. In the United Kingdom the domestic electricity supply has a frequency of 50 Hz and is about 230 V.

Students should be able to explain the difference between direct and alternating potential difference.

Distance is how far an object moves. Distance does not involve direction. Distance is a scalar quantity.

Displacement is a vector quantity.

Displacement includes both the distance an object moves, measured in a straight line from the start point to the finish point and the direction of that straight line.

Students should be able to express a displacement in terms of both the magnitude and direction.

Efficiency may also be calculated using the equation:

Students may be required to calculate or use efficiency values as a decimal or as a percentage.

The energy efficiency for any energy transfer can be calculated using the equation:

efficiency = useful output energy transfer / total input energy transfer

efficiency = useful power output / total power input

Students should be able to recall and apply both equations.

(HT only) Students should be able to describe ways to increase the efficiency of an intended energy transfer.

The force gets stronger as the distance between the objects decreases.

Students should be able to: draw the electric field pattern for an isolated charged sphere explain the concept of an electric field explain how the concept of an electric field helps to explain the non-contact force between charged objects as well as other electrostatic phenomena such as sparking.

The further away from the charged object, the weaker the field.

A charged object creates an electric field around itself.

The electric field is strongest close to the charged object.

A second charged object placed in the field experiences a force.

This is the basis of an electric motor.

A coil of wire carrying a current in a magnetic field tends to rotate.

Students should be able to explain how the force on a conductor in a magnetic field causes the rotation of the coil in an electric motor.

For electrical charge to flow through a closed circuit the circuit must include a source of potential difference.

Electric current is a flow of electrical charge. The size of the electric current is the rate of flow of electrical charge. Charge flow, current and time are linked by the equation: charge f low = current × time Q = I t charge flow, Q, in coulombs, C current, I, in amperes, A (amp is acceptable for ampere) time, t, in seconds, s A current has the same value at any point in a single closed loop.

Adding an iron core increases the strength of the magnetic field of a solenoid.

When a current flows through a conducting wire a magnetic field is produced around the wire.

The magnetic field around a solenoid has a similar shape to that of a bar magnet.

(Physics only) Students should be able to interpret diagrams of electromagnetic devices in order to explain how they work.

Students should be able to: describe how the magnetic effect of a current can be demonstrated draw the magnetic field pattern for a straight wire carrying a current and for a solenoid (showing the direction of the field) explain how a solenoid arrangement can increase the magnetic effect of the current.

The strength of the magnetic field depends on the current through the wire and the distance from the wire.

Shaping a wire to form a solenoid increases the strength of the magnetic field created by a current through the wire.

The magnetic field inside a solenoid is strong and uniform.

An electromagnet is a solenoid with an iron core.

A perfect black body is an object that absorbs all of the radiation incident on it.

A black body does not reflect or transmit any radiation.

All bodies (objects), no matter what temperature, emit and absorb infrared radiation.

Since a good absorber is also a good emitter, a perfect black body would be the best possible emitter.

The hotter the body, the more infrared radiation it radiates in a given time.

The amount of energy stored in or released from a system as its temperature changes can be calculated using the equation:

change in thermal energy = mass × speci f ic heat capacity × temperature change ∆E = m c ∆ θ change in thermal energy, ∆E, in joules, J mass, m, in kilograms, kg specific heat capacity, c, in joules per kilogram per degree Celsius, J/kg °C temperature change, ∆θ, in degrees Celsius, °C The specific heat capacity of a substance is the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius.

A system is an object or group of objects.

Students should be able to describe all the changes involved in the way energy is stored when a system changes, for common situations. For example: an object projected upwards a moving object hitting an obstacle an object accelerated by a constant force a vehicle slowing down bringing water to a boil in an electric kettle.

Throughout this section on Energy students should be able to calculate the changes in energy involved when a system is changed by: heating work done by forces work done when a current flows use calculations to show on a common scale how the overall energy in a system is redistributed when the system is changed.

There are changes in the way energy is stored when a system changes.

Students should be able to describe with examples where there are energy transfers in a closed system, that there is no net change to the total energy.

The higher the thermal conductivity of a material the higher the rate of energy transfer by conduction across the material.

Students should be able to describe, with examples, how in all system changes energy is dissipated, so that it is stored in less useful ways.

Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed.

This energy is often described as being ‘wasted’.

Students should be able to explain ways of reducing unwanted energy transfers, for example through lubrication and the use of thermal insulation.

Students should be able to describe how the rate of cooling of a building is affected by the thickness and thermal conductivity of its walls.

Required practical activity 2 (physics only): investigate the effectiveness of different materials as thermal insulators and the factors that may affect the thermal insulation properties of a material.

Everyday electrical appliances are designed to bring about energy transfers.

The amount of energy an appliance transfers depends on how long the appliance is switched on for and the power of the appliance.

Students should be able to describe how different domestic appliances transfer energy from batteries or ac mains to the kinetic energy of electric motors or the energy of heating devices.

Students should be able to describe, with examples, the relationship between the power ratings for domestic electrical appliances and the changes in stored energy when they are in use.

Work is done when charge flows in a circuit.

The amount of energy transferred by electrical work can be calculated using the equation: energy trans f erred = power × time E = P t energy trans f erred = charge f low × potential di f f erence E = Q V energy transferred, E, in joules, J power, P, in watts, W time, t, in seconds, s charge flow, Q, in coulombs, C potential difference, V, in volts, V Students should be able to explain how the power of a circuit device is related to: the potential difference across it and the current through it the energy transferred over a given time.

The braking distance of a vehicle can be affected by adverse road and weather conditions and poor condition of the vehicle.

Adverse road conditions include wet or icy conditions. Poor condition of the vehicle is limited to the vehicle's brakes or tyres.

Students should be able to: explain the factors which affect the distance required for road transport vehicles to come to rest in emergencies, and the implications for safety estimate how the distance required for road vehicles to stop in an emergency varies over a range of typical speeds.

When a force is applied to the brakes of a vehicle, work done by the friction force between the brakes and the wheel reduces the kinetic energy of the vehicle and the temperature of the brakes increases.

The greater the braking force the greater the deceleration of the vehicle. Large decelerations may lead to brakes overheating and/or loss of control.

(HT only) estimate the forces involved in the deceleration of road vehicles in typical situations on a public road.

The greater the speed of a vehicle the greater the braking force needed to stop the vehicle in a certain distance.

Students should be able to explain the dangers caused by large decelerations.

Students should be able to recall the factors that affect the size of the force on the conductor.

This is called the motor effect.

For a conductor at right angles to a magnetic field and carrying a current: f orce = magnetic f lux density × current × length F = B I l force, F, in newtons, N magnetic flux density, B, in tesla, T current, I, in amperes, A (amp is acceptable for ampere) length, l, in metres, m

When a conductor carrying a current is placed in a magnetic field the magnet producing the field and the conductor exert a force on each other.

Students should be able to show that Fleming's left-hand rule represents the relative orientation of the force, the current in the conductor and the magnetic field.

f orce = spring constant × extension F = k e force, F, in newtons, N spring constant, k, in newtons per metre, N/m extension, e, in metres, m This relationship also applies to the compression of an elastic object, where ‘e’ would be the compression of the object.

A force that stretches (or compresses) a spring does work and elastic potential energy is stored in the spring.

Students should be able to calculate relevant values of stored energy and energy transfers.

Provided the spring is not inelastically deformed, the work done on the spring and the elastic potential energy stored are equal.

Required practical activity 6: investigate the relationship between force and extension for a spring.

The extension of an elastic object, such as a spring, is directly proportional to the force applied, provided that the limit of proportionality is not exceeded.

Students should be able to: give examples of the forces involved in stretching, bending or compressing an object explain why, to change the shape of an object (by stretching, bending or compressing), more than one force has to be applied – this is limited to stationary objects only describe the difference between elastic deformation and inelastic deformation caused by stretching forces.

Weight is measured using a calibrated spring-balance (a newtonmeter).

The weight of an object and the mass of an object are directly proportional.

The weight of an object can be calculated using the equation: weight = mass × gravitational field strength W = m g weight, W, in newtons, N mass, m, in kilograms, kg gravitational field strength, g, in newtons per kilogram, N/kg (In any calculation the value of the gravitational field strength (g) will be given.) The weight of an object may be considered to act at a single point referred to as the object’s ‘centre of mass’.

The weight of an object depends on the gravitational field strength at the point where the object is.

Weight is the force acting on an object due to gravity. The force of gravity close to the Earth is due to the gravitational field around the Earth.

Students should be able to determine the half-life of a radioactive isotope from given information.

(HT only) Students should be able to calculate the net decline, expressed as a ratio, in a radioactive emission after a given number of half-lives.

The half-life of a radioactive isotope is the time it takes for the number of nuclei of the isotope in a sample to halve, or the time it takes for the count rate (or activity) from a sample containing the isotope to fall to half its initial level.

Radioactive decay is random.

Students should be able to explain the concept of half-life and how it is related to the random nature of radioactive decay.

Doing work on a gas increases the internal energy of the gas and can cause an increase in the temperature of the gas.

Students should be able to explain how, in a given situation eg a bicycle pump, doing work on an enclosed gas leads to an increase in the temperature of the gas.

Work is the transfer of energy by a force.

If an electrical conductor moves relative to a magnetic field or if there is a change in the magnetic field around a conductor, a potential difference is induced across the ends of the conductor.

This is called the generator effect.

An induced current generates a magnetic field that opposes the original change, either the movement of the conductor or the change in magnetic field.

Students should be able to recall the factors that affect the size of the induced potential difference/induced current.

If the conductor is part of a complete circuit, a current is induced in the conductor.

Students should be able to recall the factors that affect the direction of the induced potential difference/induced current.

Students should be able to apply the principles of the generator effect in a given context.

Heating changes the energy stored within the system by increasing the energy of the particles that make up the system.

Internal energy is the total kinetic energy and potential energy of all the particles (atoms and molecules) that make up a system.

This either raises the temperature of the system or produces a change of state.

Energy is stored inside a system by the particles (atoms and molecules) that make up the system. This is called internal energy.

In a convex lens, parallel rays of light are brought to a focus at the principal focus.

The distance from the lens to the principal focus is called the focal length.

Image height and object height should both be measured in either mm or cm.

In ray diagrams a convex lens will be represented by: A concave lens will be represented by:

A lens forms an image by refracting light.

Ray diagrams are used to show the formation of images by convex and concave lenses.

The image produced by a convex lens can be either real or virtual.

The image produced by a concave lens is always virtual.

Students should be able to construct ray diagrams to illustrate the similarities and differences between convex and concave lenses.

Students should be able to explain how a moving-coil loudspeaker and headphones work.

Loudspeakers and headphones use the motor effect to convert variations in current in electrical circuits to the pressure variations in sound waves.

The direction of the magnetic field at any point is given by the direction of the force that would act on another north pole placed at that point.

The strength of the magnetic field depends on the distance from the magnet. The field is strongest at the poles of the magnet.

A magnetic compass contains a small bar magnet. The Earth has a magnetic field. The compass needle points in the direction of the Earth’s magnetic field.

The region around a magnet where a force acts on another magnet or on a magnetic material (iron, steel, cobalt and nickel) is called the magnetic field.

The force between a magnet and a magnetic material is always one of attraction.

The direction of a magnetic field line is from the north (seeking) pole of a magnet to the south(seeking) pole of the magnet.

Most electrical appliances are connected to the mains using three- core cable.

The live wire carries the alternating potential difference from the supply.

The neutral wire completes the circuit.

The earth wire is at 0 V, it only carries a current if there is a fault.

The potential difference between the live wire and earth (0 V) is about 230 V. The neutral wire is at, or close to, earth potential (0 V).

Students should be able to explain: that a live wire may be dangerous even when a switch in the mains circuit is open the dangers of providing any connection between the live wire and earth.

The earth wire is a safety wire to stop the appliance becoming live.

The insulation covering each wire is colour coded for easy identification: live wire – brown neutral wire – blue earth wire – green and yellow stripes.

Atoms can be represented as shown in this example: Atoms of the same element can have different numbers of neutrons; these atoms are called isotopes of that element.

The number of protons in an atom of an element is called its atomic number.

Atoms turn into positive ions if they lose one or more outer electron(s).

Students should be able to relate differences between isotopes to differences in conventional representations of their identities, charges and masses.

In an atom the number of electrons is equal to the number of protons in the nucleus. Atoms have no overall electrical charge.

All atoms of a particular element have the same number of protons.

The total number of protons and neutrons in an atom is called its mass number.

Students should be able to explain how a moving-coil microphone works.

Microphones use the generator effect to convert the pressure variations in sound waves into variations in current in electrical circuits.

A force or a system of forces may cause an object to rotate.

Students should be able to calculate the size of a force, or its distance from a pivot, acting on an object that is balanced.

A simple lever and a simple gear system can both be used to transmit the rotational effects of forces.

If an object is balanced, the total clockwise moment about a pivot equals the total anticlockwise moment about that pivot.

The turning effect of a force is called the moment of the force. The size of the moment is defined by the equation: moment o f a f orce = f orce × distance M = F d moment of a force, M, in newton-metres, Nm force, F, in newtons, N distance, d, is the perpendicular distance from the pivot to the line of action of the force, in metres, m.

Students should be able to describe examples in which forces cause rotation.

Students should be able to explain how levers and gears transmit the rotational effects of forces.

Momentum is defined by the equation: momentum = mass × velocity p = m v momentum, p, in kilograms metre per second, kg m/s mass, m, in kilograms, kg velocity, v, in metres per second, m/s

The main energy resources available for use on Earth include: fossil fuels (coal, oil and gas), nuclear fuel, bio-fuel, wind, hydro- electricity, geothermal, the tides, the Sun and water waves.

The uses of energy resources include: transport, electricity generation and heating.

A renewable energy resource is one that is being (or can be) replenished as it is used.

Students should be able to: describe the main energy sources available distinguish between energy resources that are renewable and energy resources that are non-renewable compare ways that different energy resources are used, the uses to include transport, electricity generation and heating understand why some energy resources are more reliable than others describe the environmental impact arising from the use of different energy resources explain patterns and trends in the use of energy resources.

Students should be able to: consider the environmental issues that may arise from the use of different energy resources show that science has the ability to identify environmental issues arising from the use of energy resources but not always the power to deal with the issues because of political, social, ethical or economic considerations.

Newton’s First Law: If the resultant force acting on an object is zero and: the object is stationary, the object remains stationary the object is moving, the object continues to move at the same speed and in the same direction. So the object continues to move at the same velocity.

So, the velocity (speed and/or direction) of an object will only change if a resultant force is acting on the object.

Students should be able to apply Newton’s First Law to explain the motion of objects moving with a uniform velocity and objects where the speed and/or direction changes.

(HT only) The tendency of objects to continue in their state of rest or of uniform motion is called inertia.

So, when a vehicle travels at a steady speed the resistive forces balance the driving force.

Newton’s Second Law: The acceleration of an object is proportional to the resultant force acting on the object, and inversely proportional to the mass of the object.

Students should be able to estimate the speed, accelerations and forces involved in large accelerations for everyday road transport.

resultant force = mass × acceleration

(HT only) Inertial mass is a measure of how difficult it is to change the velocity of an object.

(HT only) Inertial mass is defined as the ratio of force over acceleration.

Required practical activity 7: investigate the effect of varying the force on the acceleration of an object of constant mass, and the effect of varying the mass of an object on the acceleration produced by a constant force.

F = m a

force, F, in newtons, N

acceleration, a, in metres per second squared, m/s²

mass, m, in kilograms, kg

Students should recognise and be able to use the symbol ≈ that indicates an approximate value or approximate answer.

Newton’s Third Law: Whenever two objects interact, the forces they exert on each other are equal and opposite.

Students should be able to apply Newton’s Third Law to examples of equilibrium situations.

Nuclear equations are used to represent radioactive decay.

In a nuclear equation an alpha particle may be represented by the symbol: and a beta particle by the symbol: The emission of the different types of nuclear radiation may cause a change in the mass and /or the charge of the nucleus. For example: So alpha decay causes both the mass and charge of the nucleus to decrease.

This is limited to balancing the atomic numbers and mass numbers.

Students should be able to use the names and symbols of common nuclei and particles to write balanced equations that show single alpha (α) and beta (β) decay.

So beta decay does not cause the mass of the nucleus to change but does cause the charge of the nucleus to increase.

The emission of a gamma ray does not cause the mass or the charge of the nucleus to change.

The explosion caused by a nuclear weapon is caused by an uncontrolled chain reaction.

Energy is released by the fission reaction.

Spontaneous fission is rare. Usually, for fission to occur the unstable nucleus must first absorb a neutron.

Nuclear fission is the splitting of a large and unstable nucleus (eg uranium or plutonium).

The chain reaction is controlled in a nuclear reactor to control the energy released.

The nucleus undergoing fission splits into two smaller nuclei, roughly equal in size, and emits two or three neutrons plus gamma rays.

All of the fission products have kinetic energy.

The neutrons may go on to start a chain reaction.

Students should be able to draw/interpret diagrams representing nuclear fission and how a chain reaction may occur.

Nuclear fusion is the joining of two light nuclei to form a heavier nucleus. In this process some of the mass may be converted into the energy of radiation.

(HT only) Students should be able to explain qualitatively how: (HT only) for circular orbits, the force of gravity can lead to changing velocity but unchanged speed (HT only) for a stable orbit, the radius must change if the speed changes.

Gravity provides the force that allows planets and satellites (both natural and artificial) to maintain their circular orbits.

Students should be able to describe the similarities and distinctions between the planets, their moons, and artificial satellites.

Within our solar system there is one star, the Sun, plus the eight planets and the dwarf planets that orbit around the Sun.

The Sun was formed from a cloud of dust and gas (nebula) pulled together by gravitational attraction.

Students should be able to explain: how, at the start of a star's life cycle, the dust and gas drawn together by gravity causes fusion reactions that fusion reactions lead to an equilibrium between the gravitational collapse of a star and the expansion of a star due to fusion energy.

Our solar system is a small part of the Milky Way galaxy.

Natural satellites, the moons that orbit planets, are also part of the solar system.

Changing the temperature of a gas, held at constant volume, changes the pressure exerted by the gas.

Students should be able to: explain how the motion of the molecules in a gas is related to both its temperature and its pressure explain qualitatively the relation between the temperature of a gas and its pressure at constant volume.

The molecules of a gas are in constant random motion. The temperature of the gas is related to the average kinetic energy of the molecules.

(HT only) Students should be able to use information, or draw/ interpret diagrams to show how radiation affects the temperature of the Earth’s surface and atmosphere.

(HT only) Students should be able to explain how the temperature of a body is related to the balance between incoming radiation absorbed and radiation emitted, using everyday examples to illustrate this balance, and the example of the factors which determine the temperature of the Earth.

The temperature of a body increases when the body absorbs radiation faster than it emits radiation.

(HT only) The temperature of the Earth depends on many factors including: the rates of absorption and emission of radiation, reflection of radiation into space.

(HT only) A body at constant temperature is absorbing radiation at the same rate as it is emitting radiation.

Students should be able to explain: that all bodies (objects) emit radiation that the intensity and wavelength distribution of any emission depends on the temperature of the body.

A permanent magnet produces its own magnetic field.

Induced magnetism always causes a force of attraction.

Students should be able to describe: the attraction and repulsion between unlike and like poles for permanent magnets the difference between permanent and induced magnets.

The poles of a magnet are the places where the magnetic forces are strongest.

Two unlike poles attract each other.

Two like poles repel each other.

When two magnets are brought close together they exert a force on each other.

Attraction and repulsion between two magnetic poles are examples of non-contact force.

An induced magnet is a material that becomes a magnet when it is placed in a magnetic field.

When removed from the magnetic field an induced magnet loses most/all of its magnetism quickly.

Students should be able to give examples that illustrate the definition of power eg comparing two electric motors that both lift the same weight through the same height but one does it faster than the other.

Students should be able to explain how the power transfer in any circuit device is related to the potential difference across it and the current through it, and to the energy changes over time: power = potential di f f erence × current P = V I power = current × resistance P = I R power, P, in watts, W potential difference, V, in volts, V current, I, in amperes, A (amp is acceptable for ampere) resistance, R, in ohms, Ω

Power is defined as the rate at which energy is transferred or the rate at which work is done.

A fluid can be either a liquid or a gas.

The pressure at the surface of a fluid can be calculated using the equation:

area, A, in metres squared

pressure, p, in pascals, Pa

force, F, in newtons, N

The pressure in fluids causes a force normal (at right angles) to any surface.

p = F / A

Students should be able to recall and apply this equation.

pressure = force normal to a surface / area of that surface

The pressure due to a column of liquid can be calculated using the equation: pressure = height of the column × density of the liquid × gravitational field strength [ p = h ρ g ] pressure, p, in pascals, Pa height of the column, h, in metres, m density, ρ, in kilograms per metre cubed, kg/m gravitational field strength, g, in newtons per kilogram, N/kg (In any calculation the value of the gravitational field strength (g) will be given.) Students should be able to explain why, in a liquid, pressure at a point increases with the height of the column of liquid above that point and with the density of the liquid.

Students should be able to calculate the differences in pressure at different depths in a liquid.

This creates a resultant force upwards.

This force is called the upthrust.

A partially (or totally) submerged object experiences a greater pressure on the bottom surface than on the top surface.

Students should be able to describe the factors which influence floating and sinking.

A gas can be compressed or expanded by pressure changes. The pressure produces a net force at right angles to the wall of the gas container (or any surface).

Students should be able to use the particle model to explain how increasing the volume in which a gas is contained, at constant temperature, can lead to a decrease in pressure.

For a fixed mass of gas held at a constant temperature: pressure × volume = constant p V = constant pressure, p, in pascals, Pa volume, V, in metres cubed, m Students should be able to calculate the change in the pressure of a gas or the volume of a gas (a fixed mass held at constant temperature) when either the pressure or volume is increased or decreased.

(HT only) Some effects, for example refraction, are due to the difference in velocity of the waves in different substances.

(HT only) Students should be able to use wave front diagrams to explain refraction in terms of the change of speed that happens when a wave travels from one medium to a different medium.

Required practical activity 10: investigate how the amount of infrared radiation absorbed or radiated by a surface depends on the nature of that surface.

(HT only) Different substances may absorb, transmit, refract or reflect electromagnetic waves in ways that vary with wavelength.

Students should be able to construct ray diagrams to illustrate the refraction of a wave at the boundary between two different media.

(HT only) Radio waves can be produced by oscillations in electrical circuits.

Changes in atoms and the nuclei of atoms can result in electromagnetic waves being generated or absorbed over a wide frequency range.

Ultraviolet waves, X-rays and gamma rays can have hazardous effects on human body tissue.

The effects depend on the type of radiation and the size of the dose.

Radiation dose (in sieverts) is a measure of the risk of harm resulting from an exposure of the body to the radiation.

Students should be able to draw conclusions from given data about the risks and consequences of exposure to radiation.

Ultraviolet waves can cause skin to age prematurely and increase the risk of skin cancer.

1000 millisieverts (mSv) = 1 sievert (Sv) Students will not be required to recall the unit of radiation dose.

Gamma rays originate from changes in the nucleus of an atom.

(HT only) When radio waves are absorbed they may create an alternating current with the same frequency as the radio wave itself, so radio waves can themselves induce oscillations in an electrical circuit.

X-rays and gamma rays are ionising radiation that can cause the mutation of genes and cancer.

Students should be able to describe wave motion in terms of their amplitude, wavelength, frequency and period.

The amplitude of a wave is the maximum displacement of a point on a wave away from its undisturbed position.

The frequency of a wave is the number of waves passing a point each second.

The wavelength of a wave is the distance from a point on one wave to the equivalent point on the adjacent wave.

Required practical activity 8: make observations to identify the suitability of apparatus to measure the frequency, wavelength and speed of waves in a ripple tank and waves in a solid and take appropriate measurements.

period = f requency T = f period, T, in seconds, s frequency, f, in hertz, Hz The wave speed is the speed at which the energy is transferred (or the wave moves) through the medium.

(Physics only) Students should be able to show how changes in velocity, frequency and wavelength, in transmission of sound waves from one medium to another, are inter-related.

Radioactive contamination is the unwanted presence of materials containing radioactive atoms on other materials.

Irradiation is the process of exposing an object to nuclear radiation.

The hazard from contamination is due to the decay of the contaminating atoms.

Suitable precautions must be taken to protect against any hazard that the radioactive source used in the process of irradiation may present.

The irradiated object does not become radioactive.

Students should be able to compare the hazards associated with contamination and irradiation.

The type of radiation emitted affects the level of hazard.

Students should understand that it is important for the findings of studies into the effects of radiation on humans to be published and shared with other scientists so that the findings can be checked by peer review.

Activity is the rate at which a source of unstable nuclei decays.

Activity is measured in becquerel (Bq) Count-rate is the number of decays recorded each second by a detector (eg Geiger-Muller tube).

The nuclear radiation emitted may be: an alpha particle (α) – this consists of two neutrons and two protons, it is the same as a helium nucleus a beta particle (β) – a high speed electron ejected from the nucleus as a neutron turns into a proton a gamma ray (γ) – electromagnetic radiation from the nucleus a neutron (n).

Some atomic nuclei are unstable. The nucleus gives out radiation as it changes to become more stable. This is a random process called radioactive decay.

Required knowledge of the properties of alpha particles, beta particles and gamma rays is limited to their penetration through materials, their range in air and ionising power.

Students should be able to apply their knowledge to the uses of radiation and evaluate the best sources of radiation to use in a given situation.

A driver’s reaction time can be affected by tiredness, drugs and alcohol. Distractions may also affect a driver’s ability to react.

Reaction times vary from person to person. Typical values range from 0.2 s to 0.9 s.

The observed red-shift provides evidence that space itself (the universe) is expanding and supports the Big Bang theory.

This effect is called red-shift.

Since 1998 onwards, observations of supernovae suggest that distant galaxies are receding ever faster.

Students should be able to explain: qualitatively the red-shift of light from galaxies that are receding that the change of each galaxy’s speed with distance is evidence of an expanding universe how red-shift provides evidence for the Big Bang model how scientists are able to use observations to arrive at theories such as the Big Bang theory that there is still much about the universe that is not understood, for example dark mass and dark energy.

There is an observed increase in the wavelength of light from most distant galaxies.

The further away the galaxies, the faster they are moving and the bigger the observed increase in wavelength.

The Big Bang theory suggests that the universe began from a very small region that was extremely hot and dense.

Waves can be reflected at the boundary between two different materials.

Students should be able to describe the effects of reflection, transmission and absorption of waves at material interfaces.

Waves can be absorbed or transmitted at the boundary between two different materials.

Students should be able to construct ray diagrams to illustrate the reflection of a wave at a surface.

The current through an ohmic conductor (at a constant temperature) is directly proportional to the potential difference across the resistor.

The applications of thermistors in circuits eg a thermostat is required.

The application of LDRs in circuits eg switching lights on when it gets dark is required.

Students should be able to use graphs to explore whether circuit elements are linear or non-linear and relate the curves produced to their function and properties.

Students should be able to explain that, for some resistors, the value of R remains constant but that in others it can change as the current changes.

The resistance of components such as lamps, diodes, thermistors and LDRs is not constant; it changes with the current through the component.

This means that the resistance remains constant as the current changes.

Students should be able to: explain the design and use of a circuit to measure the resistance of a component by measuring the current through, and potential difference across, the component draw an appropriate circuit diagram using correct circuit symbols.

The current through a diode flows in one direction only. The diode has a very high resistance in the reverse direction.

Required practical activity 4: use circuit diagrams to construct appropriate circuits to investiga the I–V characteristics of a variety of circuit elements, including a filament lamp, a diode and a resistor at constant temperature.

The resistance of a filament lamp increases as the temperature of the filament increases.

The resistance of a thermistor decreases as the temperature increases.

The resistance of an LDR decreases as light intensity increases.

This single force is called the resultant force.

(HT only) A single force can be resolved into two components acting at right angles to each other.

(HT only) Students should be able to: describe examples of the forces acting on an isolated object or system use free body diagrams to describe qualitatively examples where several forces lead to a resultant force on an object, including balanced forces when the resultant force is zero.

Students should be able to calculate the resultant of two forces that act in a straight line.

The two component forces together have the same effect as the single force.

A number of forces acting on an object may be replaced by a single force that has the same effect as all the original forces acting together.

(HT only) Students should be able to use vector diagrams to illustrate resolution of forces, equilibrium situations and determine the resultant of two forces, to include both magnitude and direction (scale drawings only).

Scalar quantities have magnitude only.

The length of the arrow represents the magnitude, and the direction of the arrow the direction of the vector quantity.

Vector quantities have magnitude and an associated direction.

A vector quantity may be represented by an arrow.

Students should be able to: use circuit diagrams to construct and check series and parallel circuits that include a variety of common circuit components describe the difference between series and parallel circuits explain qualitatively why adding resistors in series increases the total resistance whilst adding resistors in parallel decreases the total resistance explain the design and use of dc series circuits for measurement and testing purposes calculate the currents, potential differences and resistances in dc series circuits solve problems for circuits which include resistors in series using the concept of equivalent resistance.

There are two ways of joining electrical components, in series and in parallel. Some circuits include both series and parallel parts.

For components connected in series: there is the same current through each component the total potential difference of the power supply is shared between the components the total resistance of two components is the sum of the resistance of each component.

Within the ear, sound waves cause the ear drum and other parts to vibrate which causes the sensation of sound.

The conversion of sound waves to vibrations of solids works over a limited frequency range.

This restricts the limits of human hearing.

Sound waves can travel through solids causing vibrations in the solid.

Students should be able to: describe, with examples, processes which convert wave disturbances between sound waves and vibrations in solids. Examples may include the effect of sound waves on the ear drum explain why such processes only work over a limited frequency range and the relevance of this to human hearing.

Students should know that the range of normal human hearing is from 20 Hz to 20 kHz.

The speed of a moving object is rarely constant. When people walk, run or travel in a car their speed is constantly changing.

Typical values may be taken as: walking ̴ 1.5 m/s running ̴ 3 m/s cycling ̴ 6 m/s.

For an object moving at constant speed the distance travelled in a specific time can be calculated using the equation: distance travelled = speed × time s = v t distance, s, in metres, m speed, v, in metres per second, m/s time, t, in seconds, s Students should be able to calculate average speed for non-uniform motion.

A typical value for the speed of sound in air is 330 m/s.

Speed does not involve direction. Speed is a scalar quantity.

Students should be able to recall typical values of speed for a person walking, running and cycling as well as the typical values of speed for different types of transportation systems.

Students should be able to make measurements of distance and time and then calculate speeds of objects.

The speed at which a person can walk, run or cycle depends on many factors including: age, terrain, fitness and distance travelled.

It is not only moving objects that have varying speed. The speed of sound and the speed of the wind also vary.

Circuit diagrams use standard symbols.

Students should be able to draw and interpret circuit diagrams.

Two objects that carry the same type of charge repel.

The material that gains electrons becomes negatively charged.

Two objects that carry different types of charge attract.

Negatively charged electrons are rubbed off one material and on to the other.

The material that loses electrons is left with an equal positive charge.

When two electrically charged objects are brought close together they exert a force on each other.

When certain insulating materials are rubbed against each other they become electrically charged.

Students should be able to: describe the production of static electricity, and sparking, by rubbing surfaces describe evidence that charged objects exert forces of attraction or repulsion on one another when not in contact explain how the transfer of electrons between objects can explain the phenomena of static electricity.

Attraction and repulsion between two charged objects are examples of non-contact force.

For a given braking force the greater the speed of the vehicle, the greater the stopping distance.

(Physics only) Students will be required to interpret graphs relating speed to stopping distance for a range of vehicles.

(Physics only) Students should be able to estimate how the distance for a vehicle to make an emergency stop varies over a range of speeds typical for that vehicle.

The stopping distance of a vehicle is the sum of the distance the vehicle travels during the driver’s reaction time (thinking distance) and the distance it travels under the braking force (braking distance).

If the temperature of the system increases, the increase in temperature depends on the mass of the substance heated, the type of material and the energy input to the system.

The following equation applies: change in thermal energy = mass × speci f ic heat capacity × temperature change ∆E = m c ∆ θ change in thermal energy, ∆E, in joules, J mass, m, in kilograms, kg specific heat capacity, c, in joules per kilogram per degree Celsius, J/kg °C temperature change, ∆θ, in degrees Celsius, °C.

The specific heat capacity of a substance is the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius.

The theoretical calculations of Bohr agreed with experimental observations.

The discovery of the electron led to the plum pudding model of the atom.

The results from the alpha particle scattering experiment led to the conclusion that the mass of an atom was concentrated at the centre (nucleus) and that the nucleus was charged.

Niels Bohr adapted the nuclear model by suggesting that electrons orbit the nucleus at specific distances.

The plum pudding model suggested that the atom is a ball of positive charge with negative electrons embedded in it.

Before the discovery of the electron, atoms were thought to be tiny spheres that could not be divided.

New experimental evidence may lead to a scientific model being changed or replaced.

This nuclear model replaced the plum pudding model.

This was about 20 years after the nucleus became an accepted scientific idea.

Later experiments led to the idea that the positive charge of any nucleus could be subdivided into a whole number of smaller particles, each particle having the same amount of positive charge.

The name proton was given to these particles.

The experimental work of James Chadwick provided the evidence to show the existence of neutrons within the nucleus.

The speed of an object can be calculated from the gradient of its distance–time graph.

If an object moves along a straight line, the distance travelled can be represented by a distance–time graph.

Students should be able to draw distance–time graphs from measurements and extract and interpret lines and slopes of distance–time graphs, translating information between graphical and numerical form.

(HT only) If an object is accelerating, its speed at any particular time can be determined by drawing a tangent and measuring the gradient of the distance–time graph at that time.

Students should be able to determine speed from a distance–time graph.

Students should be able to describe the life cycle of a star: the size of the Sun much more massive than the Sun.

Fusion processes in stars produce all of the naturally occurring elements. Elements heavier than iron are produced in a supernova.

The explosion of a massive star (supernova) distributes the elements throughout the universe.

A star goes through a life cycle. The life cycle is determined by the size of the star.

Students should be able to explain how fusion processes lead to the formation of new elements.

Electrical power is transferred from power stations to consumers using the National Grid.

Step-up transformers are used to increase the potential difference from the power station to the transmission cables then step-down transformers are used to decrease, to a much lower value, the potential difference for domestic use.

Students should be able to explain why the National Grid system is an efficient way to transfer energy.

The National Grid is a system of cables and transformers linking power stations to consumers.

The radius of a nucleus is less than 1/10 000 of the radius of an atom. Most of the mass of an atom is concentrated in the nucleus.

The electrons are arranged at different distances from the nucleus (different energy levels).

The basic structure of an atom is a positively charged nucleus composed of both protons and neutrons surrounded by negatively charged electrons.

The electron arrangements may change with the absorption of electromagnetic radiation (move further from the nucleus; a higher energy level) or by the emission of electromagnetic radiation (move closer to the nucleus; a lower energy level).

power input and output, in watts, W Students should be able to: explain how the effect of an alternating current in one coil in inducing a current in another is used in transformers explain how the ratio of the potential differences across the two coils depends on the ratio of the number of turns on each calculate the current drawn from the input supply to provide a particular power output apply the equation linking the p.d.s and number of turns in the two coils of a transformer to the currents and the power transfer involved, and relate these to the advantages of power transmission at high potential differences.

Iron is used as it is easily magnetised.

A basic transformer consists of a primary coil and a secondary coil wound on an iron core.

Waves may be either transverse or longitudinal.

Longitudinal waves show areas of compression and rarefaction.

Sound waves travelling through air are longitudinal.

Students should be able to describe the difference between longitudinal and transverse waves.

The ripples on a water surface are an example of a transverse wave.

Students should be able to describe evidence that, for both ripples on a water surface and sound waves in air, it is the wave and not the water or air itself that travels.

Electromagnetic waves are transverse waves that transfer energy from the source of the waves to an absorber.

The waves that form the electromagnetic spectrum are grouped in terms of their wavelength and their frequency. Going from long to short wavelength (or from low to high frequency) the groups are: radio, microwave, infrared, visible light (red to violet), ultraviolet, X- rays and gamma rays.

Electromagnetic waves form a continuous spectrum and all types of electromagnetic wave travel at the same velocity through a vacuum (space) or air.

Students should be able to give examples that illustrate the transfer of energy by electromagnetic waves.

Our eyes only detect visible light and so detect a limited range of electromagnetic waves.

(HT only) Students should be able to give brief explanations why each type of electromagnetic wave is suitable for the practical application.

Students should be able to: describe and evaluate the uses of nuclear radiations for exploration of internal organs, and for control or destruction of unwanted tissue evaluate the perceived risks of using nuclear radiations in relation to given data and consequences.

Nuclear radiations are used in medicine for the: exploration of internal organs control or destruction of unwanted tissue.

Students should be able to: explain how the generator effect is used in an alternator to generate ac and in a dynamo to generate dc draw/interpret graphs of potential difference generated in the coil against time.

The generator effect is used in an alternator to generate ac and in a dynamo to generate dc.

The velocity of an object is its speed in a given direction. Velocity is a vector quantity.

Students should be able to explain the vector–scalar distinction as it applies to displacement, distance, velocity and speed.

(HT only) Students should be able to explain qualitatively, with examples, that motion in a circle involves constant speed but changing velocity.

Students should be able to explain: how the colour of an object is related to the differential absorption, transmission and reflection of different wavelengths of light by the object the effect of viewing objects through filters or the effect on light of passing through filters why an opaque object has a particular colour.

Reflection from a smooth surface in a single direction is called specular reflection. Reflection from a rough surface causes scattering: this is called diffuse reflection.

Wavelengths that are not reflected are absorbed.

If all wavelengths are reflected equally the object appears white.

Each colour within the visible light spectrum has its own narrow band of wavelength and frequency.

Colour filters work by absorbing certain wavelengths (and colour) and transmitting other wavelengths (and colour).

The colour of an opaque object is determined by which wavelengths of light are more strongly reflected.

Objects that transmit light are either transparent or translucent.

If all wavelengths are absorbed the objects appears black.

Students should be able to explain in qualitative terms, how the differences in velocity, absorption and reflection between different types of wave in solids and liquids can be used both for detection and exploration of structures which are hidden from direct observation.

Ultrasound waves are partially reflected when they meet a boundary between two different media.

This allows ultrasound waves to be used for both medical and industrial imaging.

P-waves travel at different speeds through solids and liquids.

Echo sounding, using high frequency sound waves is used to detect objects in deep water and measure water depth.

Ultrasound waves have a frequency higher than the upper limit of hearing for humans.

The time taken for the reflections to reach a detector can be used to determine how far away such a boundary is.

P-waves are longitudinal, seismic waves.

Seismic waves are produced by earthquakes.

S-waves are transverse, seismic waves.

S-waves cannot travel through a liquid. P-waves and S-waves provide evidence for the structure and size of the Earth’s core.

Students should be aware that the study of seismic waves provided new evidence that led to discoveries about parts of the Earth which are not directly observable.

When a force causes an object to move through a distance work is done on the object.

Students should be able to convert between newton-metres and joules.

1 joule = 1 newton-metre Students should be able to describe the energy transfer involved when work is done.

Work done against the frictional forces acting on an object causes a rise in the temperature of the object.

The work done by a force on an object can be calculated using the equation: work done = force × distance moved along the line of action of the force W = F s work done, W, in joules, J force, F, in newtons, N distance, s, in metres One joule of work is done when a force of one newton causes a displacement of one metre.

So a force does work on an object when the force causes a displacement of the object.