Different types of machines need different types of energy to make them work
Energy can be stored until it is needed
EXAMPLE QUESTIONS
How do machines use energy to make them work?
What different sources of energy do different machines use?
In what kinds of ways can energy be stored?
MACHINES NEED ENERGY TO MAKE THEM OPERATE
Energy is essential for machines. Some simple machines get the energy they need from human muscles.
Some require other sources of energy, such as electricity , heat, chemical or nuclear power, or the movement of wind or water.
Some machines keep replaceable or rechargeable energy stored inside them (batteries or wind-up springs, for example); others get heat energy from fuels, such as oil, coal and wood.
Other machines are attached to centrally supplied energy sources (electrical power lines and gas mains).
All machines need a source of energy to make them operate.
MACHINES INVOLVE THE TRANSFER OF ENERGY
All machines take energy from one source and transfer it to another.
A pair of scissors takes energy from our hands and transfers it to the cutting blades.
A car takes the stored energy in petrol and transfers it into heat in the engine and then from the engine to the wheels.
ENERGY CAN BE STORED
Energy cannot be created or destroyed but it can be stored in various forms.
One way to store it is in the form of chemical energy in a battery.
A wind up clock stores potential energy in the spring tension
