Some appliances in our homes and at school use electrical energy from the mains and some work using batteries.
Mains electricity is very powerful, making it dangerous to use in our own science investigations.
Batteries are a weaker source of electrical energy and will not generally give us an electric shock.
Appliances, like this washing machine, which use a lot of energy work off the MAINS:
Smaller appliances, which do not use a lot of energy (like this calculator), get their energy from BATTERIES:
Right, bearing all that in mind, let's have a closer look at appliances, at circuits and the use of mains and battery power.