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Count how many of the appliances use electrical energy. Now think
about where that electrical energy comes from.
Some gadgets, like mobile phones, alarm clocks, and transistor radios,
get their electrical energy from batteries which fit into the back
of them. Electrical energy is stored in the battery a bit like water
being stored in a bottle.
When you switch on your radio, or turn on a torch, you use up a little
bit of that electrical energy. It’s a bit like taking the top off
a bottle and taking a swig of water.
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When you turn off the radio you stop using the electrical energy
and what’s left is stored in the battery for next time. Once you have
used up all the electrical energy in the battery the radio will stop
working.
We call an empty battery a ‘flat’ battery and in order to make the
radio work again you either have to re-charge the battery by filling
it up with more electrical energy, or replace it with a new one.
But what about the gadgets which you plug into the wall, like the
television or vacuum cleaner? They never seem to run out of electrical
energy. Where does electrical energy come from?
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