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4.1 Energy
4.1.1 Energy changes in a system
4.1.1.1a - Energy Stores and System ChangesEnergy is a way of tracking changes in a system. In this lesson, you will practise describing where energy is stored before and after a change, without doing calculations. The key skill is to choose the system clearly, then describe which energy stores increase and which decrease.
4.1.1.1b - Energy Calculations and RedistributionEnergy calculations are a way of keeping accounts. When a system changes, energy may be transferred by heating, by a force doing work, or by electrical work when current flows. In this lesson, the aim is to calculate the size of those transfers and show, on one common scale, where the total energ...
4.1.1.2a - Kinetic EnergyKinetic energy is the energy associated with a moving object. This lesson is about one equation: how the mass and speed of an object determine its kinetic energy. For this specification point, the kinetic-energy equation is recall and apply, so you need to know it and use it accurately.
4.1.1.2b - Elastic Potential Energy in a Stretched SpringA stretched spring stores energy in its elastic potential store. This lesson is about using the given elastic potential energy equation carefully: choosing the right values, using the right units, and checking that the spring has stayed within its limit of proportionality.
4.1.1.2c - Gravitational Potential EnergyWhen an object is raised above ground level, energy is transferred to its gravitational potential energy store. This lesson is about calculating that energy gained, using the equation that AQA expects you to recall and apply. In any calculation, the value of gravitational field strength, g, will...
4.1.1.3 - Specific Heat Capacity and Required Practical 1When a material is heated and its temperature rises, energy has been transferred to its thermal energy store. Specific heat capacity tells us how much energy a material needs for a given temperature rise. In this lesson you will use the given equation and learn the required practical method for d...
4.1.1.4 - Power and Work RatePower tells you how quickly energy is transferred or how quickly work is done. Two machines can transfer the same amount of energy, but the one that does it in less time has the greater power. In this lesson, both power equations are recall-and-apply equations, so you need to know them and use th...
4.1.2 Conservation and dissipation of energy
4.1.2.1a - Conservation, Dissipation and Closed SystemsEnergy is useful because it lets us describe and predict changes, but energy is never used up in the strict physics sense. In this lesson, you will practise describing how energy is transferred usefully, stored, and dissipated in closed systems. The key exam habit is to say where the energy is st...
4.1.2.1b - Reducing Unwanted Energy Transfers and Required Practical 2Energy is not destroyed when a device, machine or building works, but not every transfer is useful. This lesson focuses on ways to reduce unwanted energy transfers, especially through lubrication and thermal insulation. It also teaches required practical activity 2, which is physics only: investi...
4.1.2.2 - EfficiencyEfficiency tells you how much of an input energy transfer becomes the output that was actually wanted. In this lesson you will use two recall-and-apply equations: one for energy transfers and one for power. You will also switch between decimal and percentage efficiencies, and for Higher tier you...
4.1.3 National and global energy resources
4.1.3a - Energy Resources, Uses and ReliabilityEnergy resources are the sources humans use to transfer energy for useful purposes. In this lesson you will sort the main resources into renewable and non-renewable groups, compare their uses for transport, electricity generation and heating, and explain why some resources are more reliable than...
4.1.3b - Environmental Impact and Energy Resource DecisionsEnergy resources are not judged only by how much energy they can supply. Their use can affect the atmosphere, land, water, habitats, health, landscapes and future generations. In this lesson you will describe those environmental impacts, explain patterns in energy-resource use from data, and eval...
4.2 Electricity
4.2.1 Current, potential difference and resistance
4.2.1.1 - Standard circuit diagram symbolsCircuit diagrams are a compact way to show electrical circuits. They do not try to draw the real apparatus; instead, they use agreed symbols so that anyone can see which components are present and how they are connected. In this lesson you will learn how to recognise, draw and interpret the stand...
4.2.1.2 - Electrical Charge and CurrentElectric current is not the same thing as energy. It is a flow of electrical charge, and its size tells you how quickly charge is flowing. This lesson builds the circuit conditions needed for charge to flow, then uses the AQA relationship between charge flow, current and time.
4.2.1.3a - Current, Resistance and Potential DifferenceCurrent, resistance and potential difference are linked, so changing one can change the others. This lesson focuses on the relationship for a single component: how current depends on the component's resistance and the potential difference across it. You will also recall and apply the equation V =...
4.2.1.3b - Required Practical 3 - Resistance in CircuitsResistance affects the current in a circuit for a given potential difference. In this required practical, you use circuit diagrams to build and check circuits, then use measurements of potential difference and current to calculate resistance. The investigation has two main parts: how the length o...
4.2.1.4a - Ohmic conductors, filament lamps and diodesDifferent circuit components do not all keep the same resistance. Some behave almost like a fixed opposition to current, but others change because they heat up or because their direction in the circuit matters. In this lesson you will compare the resistance behaviour of an ohmic conductor, a fila...
4.2.1.4b - Thermistors, LDRs And Sensing CircuitsSome resistors have a resistance that changes when their surroundings change. A thermistor responds to temperature, and an LDR responds to light intensity. In this lesson, you will use those changes to explain sensing circuits such as thermostats and lights that switch on when it gets dark.
4.2.1.4c - I-V Characteristics and Required Practical 4An I-V characteristic is a graph that shows how the current through a component changes as the potential difference across it changes. The shape of the graph is evidence: it tells you whether the component behaves linearly, whether its resistance changes, and how its properties match its function...
4.2.2 Series and parallel circuits
4.2.2a - Series Circuits and Equivalent ResistanceIn a series circuit, components are joined in one continuous route, so the same current passes through every component in that route. The supply potential difference is shared between the components, and series resistances add together. These three ideas let you construct, check and calculate dc...
4.2.2b - Parallel Circuits and Circuit CalculationsParallel circuits give electric charge more than one route through a circuit. That changes how potential difference, current and resistance behave, so the first job in any circuit question is to recognise the connections before doing any arithmetic. In this lesson, you will use parallel-circuit r...
4.2.3 Domestic uses and safety
4.2.3.1 - Direct and alternating potential differencePotential difference is often called voltage, and it is measured in volts, V. This lesson compares two ways a supply can provide potential difference: direct and alternating. You also need the key UK mains facts: mains electricity is ac, has a frequency of 50 Hz, and is about 230 V.
4.2.3.2 - Mains Electricity and Three-Core Cable SafetyMost electrical appliances are connected to the mains with a cable containing separate wires for live, neutral and earth. The colours and functions of these wires matter because the live wire can be dangerous even when an appliance is not working. This lesson focuses on what each wire does, what...
4.2.4 Energy transfers
4.2.4.1 - Electrical Power in CircuitsElectrical power tells you how quickly a circuit device transfers energy. In this lesson, the device might be a resistor, lamp, heater, motor, or any other component where energy changes happen. You need to connect power to the potential difference across the device, the current through it, and t...
4.2.4.2 - Energy Transfers in Everyday AppliancesEveryday electrical appliances are designed to transfer energy in useful ways. A fan transfers energy to the kinetic energy store of moving air, while a kettle transfers energy to the thermal energy store of water. In this lesson you will connect those transfers to power ratings, time, charge flo...
4.2.4.3 - The National GridThe National Grid transfers electrical power from power stations to consumers such as homes, schools, shops and factories. Its key idea is simple but important: use transformers and cables so that electricity can travel long distances with less energy wasted by heating the cables. In this lesson,...
4.2.5 Static electricity
4.2.5.1 - Static ChargeStatic electricity is the set of effects caused when electric charge builds up on an object instead of flowing steadily as a current. In this physics-only lesson, you will describe how rubbing insulating materials can produce static electricity and sparking. You will also explain the observations...
4.2.5.2 - Electric FieldsCharged objects can affect other charged objects even when they are not touching. This physics-only lesson explains that effect using the idea of an electric field: a region around a charged object where another charged object can experience a force. You will also learn the field pattern for an i...
4.3 Particle model of matter
4.3.1 Changes of state and the particle model
4.3.2 Internal energy and energy transfers
4.3.3 Particle model and pressure
4.4 Atomic structure
4.4.1 Atoms and isotopes
4.4.2 Atoms and nuclear radiation
4.4.3 Hazards and uses of radioactive emissions and of background radiation
4.4.4 Nuclear fission and fusion
4.5 Forces
4.5.1 Forces and their interactions
4.5.2 Work done and energy transfer
4.5.3 Forces and elasticity
4.5.4 Moments, levers and gears
4.5.5 Pressure and pressure differences in fluids
4.5.6 Forces and motion
4.5.7 Momentum
4.6 Waves
4.6.1 Waves in air, fluids and solids
4.6.2 Electromagnetic waves
4.6.3 Black body radiation
4.7 Magnetism and electromagnetism
4.7.1 Permanent and induced magnetism, magnetic forces and fields
4.7.2 The motor effect
4.7.3 Induced potential, transformers and the National Grid
4.8 Space physics (physics only)
4.8.1 Solar system, orbital motion and satellites
4.8.2 Red-shift and the expanding universe
4.9 Key ideas
4.9 Key ideas in physics