energy transfers

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.

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.

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.

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.

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.

Convection

Transfer of heat energy in liquids and gases through the movement of particles.

Convection current

The movement of warm fluid rising and cool fluid sinking.

Warm fluid

Less dense fluid that rises.

Cool fluid

More dense fluid that sinks.

Heating a fluid

Makes its particles move faster and spread further apart.

Density

How much matter is packed into a certain volume.

Convection example

Boiling water or warm air rising.

Why convection happens

Heating makes liquids and gases expand, making the hot areas less dense so they rise while cooler, denser areas sink.

Modelling convection

Observing and describing convection currents in a liquid.

Convection current diagram

A diagram showing the movement of warm and cool fluid as heat is transferred.

Radiation

Transfer of heat energy without needing particles or matter.

Thermal radiation

Infrared electromagnetic radiation that transfers heat.

Infrared waves

Electromagnetic waves that transfer heat and have a longer wavelength than visible light.

Vacuum

A space with no particles.

Radiation in space

Radiation can travel through a vacuum, which is how heat from the Sun reaches Earth.

Speed of infrared waves

300,000,000 m/s, the same speed as light.

Absorption

When an object takes in radiation.

Reflection

When radiation bounces off a surface.

Best emitter

Matt black surfaces are the best emitters of thermal radiation.

Worst emitter

Shiny surfaces are the worst emitters.

Best absorber

Matt black surfaces are the best absorbers of thermal radiation.

Worst absorber

Shiny surfaces are the worst absorbers because they reflect most radiation away.

Good emitters and absorbers

Surfaces that are good emitters are also good absorbers.

Conduction

Heat transfer mainly in solids, where heat moves between touching particles.

Radiation

Heat transfer using electromagnetic waves, with no particles involved.

Thermal insulator

A material used to reduce heat transfer.

Independent variable

The thing that is changed in an investigation.

Dependent variable

The thing that is measured or recorded.

Control variable

Something that is kept the same throughout an investigation.

Hazard

Something that could cause a problem, accident or injury.

Risk

What might happen as a result of a hazard.