Energy Stores & Systems

What are the 8 energy stores?

• Thermal - heat energy

• Kinetic - energy of moving objects

• Gravitational Potential - energy due to an object's height

• Elastic Potential - energy in stretched or compressed objects

• Chemical - stored energy in fuels, food, or batteries

• Magnetic - energy in magnetic fields

• Electrostatic - energy between electric charges

• Nuclear - energy stored in atomic nuclei

How is energy transferred?

Energy is transferred:

• Mechanically by a force doing work.

• Electrically with work done by moving charges.

• Radiation by light or sound.

What is a system?

A system is a single object or multiple subjects that is/are being studied.

What happens to energy when a system is changed?

When a system is changed, energy is transferred into or away from the system between objects in the system or between different types of energy stores.

What are closed systems?

Closed systems are systems where neither matter nor energy can enter or exit and the net change in the total energy is always 0.

How is energy transferred by heating in a kettle?

• Water is the system as it is the object studied.

• Energy is transferred electrically to the kettle’s heating element and the heating element transfers energy by heating to the water, causing the water’s temperature to rise

What is ‘work done’?

Work done is the energy transferred when a force is applied to an object, causing it to move in the direction of the force or when work is done against resistance in a circuit.