Who knew that those tasty spuds can also do double-duty as an undercover battery? Believe it or not, the common potato has the capacity to create enough electrochemical energy to power a small digital clock. The trace amount of acid and salt in the potato serves as an electrolyte and makes an excellent conductor.
What You Need:
2 potatoes (or one potato cut in half)
2 short pieces of copper wire
2 galvanized nails
3 alligator clips
Piece of sandpaper or steel wool
Low-voltage LED clock or watch
What You Do:
Have your child remove the battery from the battery compartment of the clock or watch.
Ask her to number the potatoes as "1" and "2."
Insert one nail into each potato, as well as the copper wire.
Have her use one alligator clip to connect the copper wire in potato number 1 to the positive (+) terminal in the clock's battery compartment.
Use the other alligator clip to connect the nail in potato number 2 to the negative (-) terminal in the clock's battery compartment.
Use the third alligator clip to connect the nail in potato 1 to the copper wire in potato 2. What happens?
Does your child think she can produce more energy by linking potatoes in a series?
Have her try experimenting with different objects; will a lemon power the clock? How about an orange?