Human Battery Power
To demonstrate that a human body can be used as a battery by producing an electrical current.
Theory & Background
Have you ever wondered about this fascinating scientific process? Batteries are devices that store chemical energy and convert it to electrical energy. Consisting of one or more voltaic cells, batteries come in various sizes and forms and are integrated into most electronic and portable devices.
Required Materials
- Copper Plate
- Aluminum Plate
- Micro Ammeter (a measuring instrument used to measure the electric current in a circuit, can be found at your local Radio Shack store)
- 2 Alligator / Crocodile Clips (a temporary electrical connector, named for its resemblance to a crocodile's jaws)
- Lead Wire
- 2 Blocks of Wood
- A human volunteer
Estimated Time
About 15-30 minutes to set-up, another few minutes to conduct the experiment.
Step-By-Step Procedure
Mount the copper plate and the aluminum plate to separate blocks of wood.
Connect one of the Micro Ammeter's terminals to the copper plate and attach with a Crocodile clip.
Connect the other Micro Ammeter's terminal to the aluminum plate and attach with a Crocodile clip.
Have the human volunteer stand between the two plates and hold each one in their hands.
Follow steps 1-4
Place both hands in water.
Once again, have a human volunteer (with wet hands) stand between the plates and hold each one.
Experiment Tips
- Make sure both the copper and aluminum plates are clean before using them. Dirty plates can interfere in the experiment and prevent accurate results.
Observation
When the human grabs each plate, an electric current is generated on the Micro Ammeter, indicating an electrical charge. If the meter doesn't move, it's possible the connections are wrong or not secure. In the case of no readings, try cleaning the plates and reversing the connections.
Result & Conclusion
Placing your hands on the metal plates causes the effect of a battery charge. Your hands contain a thin film of sweat that produces a chemical reaction similar to battery acid when placed on the metal plates. Your hands take negatively charged electrons away from the copper plate and transfer them to the aluminum plate, causing it to be negatively charged. The variance in charges between the places produces an electrical current which flows through your body and displays on the meter. Results For Second Version In the version where the human's hands are wet, the reading on the current meter is higher than when the hands were not wet. The human body resists the flow of current through the skin. When wet hands are placed on the plates, the resistance to current is decreased thus increasing the flow of current and creating a higher result on the meter.