A simple, but interactive circuit to teach kids about electricity is a light with switch. In this experiment kids can make a flashlight circuit. Instead of the flashlight circuit being placed inside of a plastic flashlight case, it will be set up on a table where each piece is is easy to see.
- Insulated copper wire(about 2 feet)
- Wire stripper
- single-pole switch
- incandescent light bulb
Step 1: Cut the insulated wire in 3 equal size pieces.
Step 2: Strip 1/2" of insulation off the end of each wire.
Step 3: Attach both ends of the loose wire to the battery holder. Connect one side to the positive (+) side and the other side to the negative (-) side. Do not insert the battery yet.
Step 4: Connect the other side of the positive wire to one side of the switch.
Step 5: Connect one side of the 3rd wire that was prepared in Step 1 to the other side of the switch.
Step 6: Connect the other side of the wire just connected in Step 5 to one side of the light bulb base. Selecting the right light bulb is the key to keeping this experiment simple. Light bulbs are rated for a small range of voltage. Select a light bulb that can be powered from the amount of battery power that you plan to provide.
Step 7: Using the loose side of the wire connected to the negative side of the battery, connect the other side of the light bulb base.
The lemon and the potato act like a low-power battery. This experiment shows how a wet cell battery works. Chemicals in the fruit or vegetable create a negative charge in the zinc strip. Electrons move into the zinc strip and travel up the wire attached. The electrons then travel through the voltmeter which measures the voltage drop and end up in the copper strip which becomes the positive end of the circuit. Pardon the pun, but from this experiment we can say that it is possible to "produce electricity".
Oberlin College: Demonstration of lemon battery powering a buzzer.
U.S. Dept. of Energy: Calculating Lemon Battery Power Q&A