Conservation of Energy
Physics: AQA GCSE Higher, topic 1.1.13
Conservation of Energy
The principle of the conservation of energy says that energy cannot be created or destroyed. Energy can only be transformed from one store of energy into another. There are four ways that energy can be transformed:
Mechanical work
- Energy transferred from one object to another via a force is an example of mechanical work.
- When an object falls from a building, the weight does mechanical work to transfer energy from the gravitational potential store to the kinetic store.
- When you push a wheelchair, energy is transferred to the kinetic store of the wheelchair.
Electrical work
- An electrical current transfers energy from one object to another, such as a battery powering a torch.
Heating
- Heating an object transfers energy to the object's internal store of energy.
- The internal energy is the sum of the energy in the kinetic and chemical stores of an object's particles.
Waves
- Light and other types of waves can transfer energy from one object to another.
E.g. - An object hitting an obstacle
- The object's energy is in the kinetic store at the start because it is moving.
- When the object collides with the obstacle, energy is converted to:
- The kinetic store of the obstacle (making it move).
- The thermal store of the object and the obstacle (the particles in the object and the obstacle vibrate more).
- Some energy remains in the object's kinetic store as it moves away after the collision.
Test yourself on Conservation of Energy
What type of energy transformation is taking place here?
Which of these is NOT an example of electrical work?