Bottle dynamo

A bottle dynamo is a device that uses the energy created when moving to generate electricity. It's like a generator, but instead of being powered by fuel, it uses energy from your bicycle's spinning wheels. The bottle dynamo is made up of two parts: a small plastic or metal cylinder called a 'generator', and a metal disc, called a 'dynamo', which has magnets in it. The generator and the dynamo are connected and when you spin the bike's wheels, a magnetic force causes the dynamo to spin too. This movement creates electricity, which is then stored or used to power lights or other electrical devices.