physics

Chemical energy stores include fuels, food, or the chemicals found in batteries. The energy is transferred during chemical reactions.

Kinetic energy stores describe the energy an object has because it is moving.

Gravitational potential energy stores are used to describe the energy stored in an object because of its position, such as an object above the ground.

Elastic potential energy stores describe the energy stored in a springy object when you stretch or squash it.

Thermal energy stores describe the energy a substance has because of its temperature.

Energy can be stored in a variety of different energy stores.

Energy is transferred by heating, waves, electrical current, or by a force when it moves an object.

When an object falls or gains speed, its store of gravitational potential energy decreases and its kinetic energy store increases.

When a falling object hits the ground without bouncing back, its kinetic energy store decreases. Some or all of its energy is transferred to the surroundings - the thermal energy store of the surroundings increases, and energy is also transferred by sound waves.

Energy cannot be created or destroyed.

Conservation of energy applies to all energy changes.

A system is an object or a group of objects.

A closed system is an isolated system in which no energy transfers take place out of or into the energy stores of the system.

Energy stores can be transferred between energy stores within a closed system. The total energy of the system is always the same, before and after, any such transfers.