Batteries store electrical energy. Some, like conventional flashlight batteries, are used then thrown away. Others are rechargeable. On the island, we had a car battery which was used to power various pieces of Rough Science apparatus but over time the battery became discharged. We were given the challenge of recharging it.
How does a battery work?
Every atom consists of a positively charged nucleus called a proton surrounded by a number of smaller, negatively charged particles called electrons. If atoms lose or gain electrons, they are left with a positive or negative charge and they are then called ions. In an electrically conducting solid such as a wire, some of the negatively charged electrons are able to move around fairly freely around the fixed array of positively charged protons. Although these 'free' electrons can move, there is a force which keeps the electrons — and so the charge — evenly spread along the length of the wire.
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