Kitchen Science Club Makes and Tests Homemade Batteries.
The children inserted galvanised nails and penny coins into lemons and then connected them up with numerous alligator clip wires to illuminate LEDs. The lemon batteries were also tested with a voltmeter, prior to comparing them to other home made batteries made from a potato, a kiwi fruit, an orange and an apple.
The children learnt that these batteries rely on the zinc from the nail dissolving in the acidic juice of the fruit / veg, and in so doing, leaving electrons behind in the nail. These electrons prefer to be with the copper in the coin and so travel through the connecting wires to the copper metal. It is the flow of these electrons which is the electricity.
To re-inforce the importance of the acid in allowing electricity to flow between the 2 different metals, some children also had the chance to make ice-cube tray batteries using galvanised nails, copper wire and an acid. The children tested either vinegar, lemonade or fizzy water as the acid, and successfully lit their LED on each occasion.
(Note: All of the homemade batteries made in science club were low voltage and were safe, but the children were still reminded never to play with any electricity in the home.)