Food Batteries and Clocks

A Battery is an example of electrochemistry - using a chemical reaction to generate electricity. In most batteries there are two different types of metal that, because of their properties, are capable of producing an electric potential.

Where does the food come in? In order for the electricity to flow in situations other than within metals it needs an electrolyte - a solution that contains charged particles called ions. Many foods can provide the electrolyte needed to make a battery. Citric fruits in particular are good at this because among the ions present are those that make the citric fruits acidic - and acids often help with the electrical conductivity.

Depending on what show you see - you might see a lemon light up a light buld, or orange juice run a clock. Actually, it is the different metals that are mostly responsible for making these events occur - but without the food providing the conducting solution those metals wouldn't do a thing!

Here are some links

Fun with Franklin - a page with kid activities for electricity - includes lemon battery

Lemon Energy - another page with the lemon battery demonstration

Lemon Dud - An email archive about why the lemon battery might not always work