Materials:

• A lemon

• A small shallow dish

• 2,5 cm by 5 cm strips of paper towel

• 5 copper coins (pennies)

• 5 coins made from a metal other than copper

   First, squeeze the lemon juice over the dish.

   Then soak the strips of paper towel in the lemon juice.

   Now build a pile of coins, alternating copper with non-copper coins. Slide a strip of paper towel soaked in lemon juice between each coin.

   Wet a fingertip on each hand, and hold the stack of coins between your wet fingers.

   What's going on? You received a mild electric charge because you just built a basic battery. This type of battery is the forerunner of the batteries we use today. Lemon juice is an acidic solution that conducts the electricity produced by the two types of metals used to make the coins.