The hand battery
To do and notice
Put your left hand on the aluminum plate and your right hand on the copper plate. An electric current flows which you cam observe on the meter.
Try various combination, such as copper and aluminum, copper and copper, etc. in order to get clear indications on the meter you may want to rub the plates with your hands.
Try making you hands moist by breathing on them. Does this have any effect on the meter current?
Try touching the copper and aluminum plates with one finger of each hand at a time, then two fingers, and three, etc.
Have one person put a hand on the copper plTe and another person put one hand on the aluminum plate then join hands together.
What is going on
Your body acts like the acid in a battery. A different chemical reaction takes place when your hand, which is slightly damp and salty, touches the copper plate than when your hand touches the aluminum plate. One of these reactions takes electric charge away from the copper plate, and the other reaction adds charge to the aluminum plate.
The excess electric charge on the aluminum plate then flows through the meter and then back to the copper plate to equalize the charge which is missing there.
Developed by the GE Volunteers in partnership with the Museum of Arts and Sciences (MOAS) – Daytona Beach, FL