Physics - Energy transfers and stores

1. Energy is the ability to do work 

 

Energy is the ability to do work. 

We do work when we move an object a certain distance in the direction of the force. 

Energy is measured in joules (J). 

Energy can't be created or destroyed. 

Energy can only be stored or transferred. 

Some types of energy can be stored and transferred. 

Some types of energy is transferred but not stored. 

The amount of energy transferred to useful forms is often called the "work done" 

 

1. Objects have different energy stores 

 

Energy can be found in different stores: internal, chemical, elastic potential, electrostatic, gravitational potential, kinetic, magnetic, nuclear. 

All objects have energy in an internal energy store (unless they are at a temperature of absolute zero). 

Objects have more energy in their internal energy store when their temperature rises. 

Hot objects have energy stored in their internal energy store. 

Objects raised against the pull of gravity have energy in their gravitational potential energy store. 

Objects with chemical bonds have energy in their chemical energy store. 

Moving objects have energy in their kinetic energy store. 

Objects being stretched or squashed have energy in their elastic potential energy store. 

When magnetic materials attract or repel each other they have energy in their magnetic energy store. 

When charged particles attract or repel each other they have energy in their electrostatic energy store. 

Atomic nuclei have energy in their nuclear energy store. 

 

1. Energy can be transferred in different directions 

 

When work is done, energy is transferred. 

Energy may be transferred in different directions. 

This is summarised in the diagram below (where each circle represents an energy store): 

1) Energy can be transferred into or out of a system (or group of objects). 

2) Energy can be transferred between different objects in a system. 

3) Energy can also be transferred between different energy stores. 

 

1. Energy can be transferred mechanically, electrically, by heating or by radiation (light and sound) 

 

Energy can be transferred mechanically. 

For example, energy in a drill's kinetic energy store is transferred mechanically to the surroundings. 

Energy can also be transferred electrically. 

However, energy can't be stored as electrical energy. 

A battery can store energy that's transferred electrically as chemical energy. 

Energy can also be transferred by heating. 

For example, in a power station, chemical energy in burning fuel is transferred by heating boilers. 

If you could see inside a boiler, you'd be able to see flames, it would also be very noisy.…