Look Ma - I'm a battery!

Look Ma, I’m a Battery

A DC microammeter is an instrument that measures the electric current in a circuitIn a nutshell, a battery uses a chemical reaction to produce an electrical current.  In this experiment, we will create an electric current using nothing more than our own bodies (Reeko promises this won’t hurt…. much).

  1. Mount the copper and aluminum metal plates to two separate pieces of wood.
  2. Connect one plate to one of the DC microammeter’s terminals using an alligator clip and the hookup wire.  Connect the other plate to the second terminal.  A DC microammeter, which is an instrument that measures the electric current in a circuit, can be purchased from your local Radio Shack, electronics hobbyist, or auto store.
  3. Now place one hand on each plate.

You should see an electric current generated on the meter.  If you don’t see a reading then simply reverse the connections.  If you still don’t see a reading then you may need to clean the metal plates (or get a pair of better reading glasses).

When you place your hands on the metal plates, a thin film of sweat on your hands acts just like the acid in a battery, producing a chemical reaction with the copper plate and a chemical reaction with the aluminum plate.  Your hand actually takes negatively charged electrons away from the copper plate (leaving positive charges behind) and gives electrons to the aluminum plate (causing it to become negatively charged).  This difference in charges produces an electrical current which flows through the meter.

  1. Wet both hands.
  2. Once again, place one hand on each plate.

Metals are very efficient at this electrical current we have created.  Your body resists the flow of current (through the skin).  When you wet your hands you greatly decrease the resistance and thus increase the current giving you a higher reading on the meter.

Click to get puzzle piece!

Experiment Supplies

Supplies: Microammeter, Copper plate, Aluminum plate, Wood blocks

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