The second round of Science Club sessions involved making and testing homemade batteries.
The children inserted galvanised nails and penny coins into cucumber segments. Then, using voltmeters, they discovered that this set-up was generating a small amount of elecrticity.
By connecting several of these cucumber battery cells with numerous alligator clip wires, the children were able to illuminate LEDs.
Subsequently, the children made and tested potato and apple battery cells and compared them to the cucumber cells.
The children learnt that these batteries rely on the zinc from the nail dissolving in the ionic 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 whizz 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 ionic liquid 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 ionic liquid (either vinegar, fizzy water or salty water).
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.