1.7Motion, Forces and Energy

Energy, Work and Power — Cambridge IGCSE Physics 0625 Revision Notes & Topical Questions

15 min read 28 parts Lesson 57 of 91 Unit quiz

📚 Cambridge IGCSE Physics 0625 Hub / Topical Revision

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Lesson summary

1.7 Energy, Work and Power (Part 1) — IGCSE PHYSICS notes: Name the seven energy stores and four transfer pathways and describe energy transfers in a system.Energy — energy is a property that is stored in objects or transferred between them, measured in joules (J).System — a syst…

Change means transfer
Not stores
Falling object
Spring and ball
Rolling ball
Wasted energy

Part 1 of 7Energy and systems

Energy and systems

Energy

Energy energy is a property that is stored in objects or transferred between them, measured in joules (J).

System

System a system is an object or group of objects being studied.
It can be as large as the Universe or as small as an apple on a table.
Defining the system gives a starting and stopping point for the transfers you consider.

Change means transfer

Change means transfer nothing changing means no energy is transferred, and a change such as a falling apple transfers energy.

Part 2 of 7The seven energy stores

Store	When energy is in it
Kinetic	Moving objects
Gravitational potential	Objects lifted in a gravitational field
Chemical	Fuels, food and batteries, changed by chemical reactions
Elastic (strain)	Objects stretched, squashed or bent
Nuclear	Atomic nuclei, released in nuclear reactions
Electrostatic	Charges such as electrons and protons interacting
Internal (thermal)	All objects, more when hotter

Not stores
- electrical, light and sound are not stores, because they are transfer pathways.

Part 3 of 7Energy transfer pathways

Pathway	What happens	Example
Mechanical work done	A force acts on an object	Pushing, pulling, stretching, squashing
Electrical work done	Charge moves through a potential difference	Current in a circuit
Heating	Energy passes from hotter to colder by particles	Hot coffee warming a mug and hands
Waves	Energy carried by electromagnetic, sound or other waves	Light from a lamp

Part 4 of 7Describing a transfer

Define the system.

Name the store that energy leaves.

Name the store that energy enters.

Name the transfer pathway between them.

Mention any useful and wasted outputs to the surroundings.

Part 5 of 7Typical transfers

Torch

Torch energy goes from the chemical store of the cells to the thermal store of the bulb by electrical work done.
It then leaves the bulb usefully as light and wastefully by heating.

Falling object

Falling object energy goes from gravitational potential to kinetic by mechanical work done, because the weight acts over the height of the fall.

Kettle

Kettle consider the energy from the thermal store of the element to the thermal store of the water, with some dissipated.

Part 6 of 7More energy transfers

Spring and ball

Spring and ball a spring transfers energy from the elastic store to the kinetic store by mechanical work.

Rolling ball

Rolling ball a ball rolling downhill transfers energy from the gravitational potential store to the kinetic store.

Wasted energy

Wasted energy name the store, usually the thermal store of the surroundings.

Part 7 of 7More from the specification

Key terms

Term	Meaning
Energy	A property that is stored or transferred, measured in joules.
System	An object or group of objects being studied.
Energy store	A place where energy is held, such as kinetic or thermal.
Transfer pathway	The way energy moves between stores, such as heating or work done.
Joule (J)	The unit of energy.
Dissipated	Spread out to the surroundings, usually as thermal energy.

Avoid these mistakes

Listing light or sound as energy stores — they are transfer pathways.

Naming only one store and no pathway when describing a transfer.

Saying energy is "used up" — it is transferred.

Forgetting to define the system and drifting back to how the electricity was generated.

Last updated: 15 October 2026