energy transfers
kinetic energy
L1 — Kinetic Energy
Energy: The ability to do work.
Kinetic energy: The energy an object has because it is moving.
Potential energy: Stored energy that can be used to do work.
Kinetic energy examples: Walking, running, buses and comets.
Thermal energy: Internal kinetic energy caused by the random movement and vibration of particles.
Thermal energy examples: Human bodies, hot coffee and stoves.
Light energy: Electromagnetic radiation that travels as waves and can be seen by the human eye.
Light energy examples: Sunlight, lights and infrared radiation.
Sound energy: Mechanical energy produced by vibrating objects that travels through solids, liquids or gases.
Sound energy examples: Vocal cords, musical instruments, thunder, engines and speakers.
Electrical energy: Energy from the movement of electric charges, usually electrons, through a conductor.
Electrical energy examples: Batteries and lightning.
Kinetic energy and mass: A heavier object moving at the same speed has more kinetic energy.
Kinetic energy and speed: A faster-moving object has more kinetic energy.
Kinetic energy factors: Kinetic energy depends on the mass and speed of an object.
L2 — Potential Energy
Potential energy: Stored energy that an object or system has because of its position, arrangement or state.
Gravitational potential energy: Energy stored in an object because of its height.
Gravitational potential energy examples: Aeroplanes, kites and mugs on a table.
Chemical energy: Energy stored in chemical bonds between atoms and molecules.
Chemical energy examples: Food, muscles and fuels.
Electrostatic energy: Energy stored when electric charges are moved closer together or further apart.
Electrostatic energy examples: Thunderclouds and Van de Graaff generators.
Elastic potential energy: Energy stored when an object is stretched or squashed.
Elastic potential energy examples: Drawn catapults, compressed springs and inflated balloons.
Nuclear energy: Energy stored in the nucleus of an atom.
Nuclear energy examples: Uranium and nuclear reactors.
L3 — Elastic Potential Energy
Elastic potential energy: Energy stored when an object is stretched or squashed.
Spring extension: The increase in length of a spring when a force is applied.
Force and extension: As the force increases, the extension of a spring increases.
Hooke’s Law: The extension of an elastic object is directly proportional to the force applied, as long as the limit of proportionality is not exceeded.
Directly proportional: When one value increases, the other increases at the same rate.
Limit of proportionality: The point where the extension of a spring stops being directly proportional to the force.
Elastic deformation: When an object returns to its original length after the force is removed.
Inelastic deformation: When an object does not return to its original length after the force is removed.
Stretching beyond the elastic limit: The spring becomes permanently stretched and may eventually break.
L4 — Energy Transfers
Energy transfer: The movement of energy from one object or location to another without changing its form.
Energy transformation: A change from one form of energy into another form.
Example of energy transfer: Thermal energy moving from a stove to a pan.
Example of energy transformation: Chemical energy in food changing into kinetic energy in muscles.
Law of conservation of energy: Energy cannot be created or destroyed, only changed from one form to another.
Total energy: The total amount of energy stays the same, so total input energy equals total output energy.
Wasted energy: Energy that does not do useful work.
Dissipated energy: Wasted energy that spreads out into the surroundings and cannot be easily reused.
Energy flow diagram: A diagram that shows the input and output energies of a device.
Useful energy: Energy that does the job a device is designed to do.
Wasted heat energy: Heat produced by a device that is not designed to get warm.
Wasted sound energy: Sound produced by a device that is not designed to make noise.
Energy transfers in a drill: Chemical energy in the battery is transferred into movement, sound and heat energy.
Open energy system: An energy system where energy can enter or leave the system.
Closed energy system: An energy system where energy does not enter or leave the system.
L5 — Generating Electricity
Energy resource: A source that can provide energy for use.
Fossil fuels: Coal, crude oil and natural gas that are used to generate electricity.
Turbine generator: A system used to generate electricity where something turns a turbine, which turns a generator.
Turbine: A machine that spins when pushed by something such as steam, wind or water.
Generator: A device containing a magnet and coil of wire that produces electricity when the turbine turns it.
National grid: The system used to distribute electricity to people who need it.
Coal power station stages: Coal is burned, water is turned into steam, the steam spins a turbine, and the turbine turns a generator to produce electricity.
Boiler: Uses thermal energy to turn water into steam.
Step-up transformer: Increases voltage and lowers current to reduce heat loss before electricity is sent through the national grid.
Fossil fuel energy transformation: Chemical energy → thermal energy → kinetic energy → electrical energy.
Advantages of fossil fuels: They are easily available, reliable, can produce large amounts of energy and can operate 24/7.
Disadvantages of fossil fuels: They produce carbon dioxide, can damage the environment through mining, can cause oil spills, produce sulphur dioxide and are non-renewable.
Non-renewable: A resource that will eventually run out because it cannot be replaced quickly.
Energy crisis: A situation where there is a high demand for energy but limited energy resources available.
Australian electricity generation: In 2024, fossil fuels produced 64% of Australia's electricity and renewables produced 36%.
Coal power station environmental impacts: Carbon dioxide contributes to global warming, sulphur dioxide can cause acid rain, and coal mining can damage the environment.
Coal power station social impacts: They can create jobs and provide a reliable supply of electricity.
Coal power station financial impacts: Coal has costs for mining and transporting, but power stations can create jobs and provide energy.