Energy Stores and Systems

Energy is Transferred Between Stores

When energy is %%transferred%% to an object, the energy is %%stored%% in one of the object’s %%energy stores%%.

%%Energy stores%% you need to know:

1) Thermal energy stores 2) Kinetic energy stores 3) Gravitational energy stores 4) Chemical energy stores

5)Potential energy stores 6) Magnetic energy stores 7) Electrostatic energy stores 8) Nuclear energy stores

Energy is transferred %%mechanically%% (by a %%force doing work%%), %%electrically%% (work done by %%moving things%%), by %%heating%% or %%radiation%% (%%light%% or %%sound%%).

When a System Changes, Energy is Transferred

1. A system means a single object or a group of objects
2. When a system changes, energy is transferred. It can be transferred into or away from the system, between different objects in the system or between different types of energy stores.
3. Closed systems are systems where neither matter nor energy can enter or leave. The net change in the total energy of a closed system is always zero.

Energy can be transferred by heating

1. Take the example of boiling water in a kettle - you can think of the water as the system. Energy is transferred to the water (from the kettle’s heating element) by heating, into the water’s thermal energy stores (causing the temperature of the water to rise).
2. You could also think of the kettle’s heating element and the water together as a two-object system. Energy is transferred electrically to the thermal energy store of the kettle’s heating element which transfers energy by heating to the water’s thermal energy store.

Energy can also be transferred by doing work

Work done is just another way of saying energy transferred. Work can be done when current flows(against resistance in a circuit) or by a force moving an object.