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 investigations.
Batteries are weaker source of electrical energy and will not give us an electric shock!
Appliances which use a lot of energy work off the MAINS:
Smaller appliances, which do not use a lot of energy, get their energy from BATTERIES: