Potato Powered Clock

Theory: Potato as a Battery

Hypothesis: Potatoes have starch in them which is a natural sugar that can be broken down naturally for a release of energy and generate enough power to run a digital clock.

Problem Statement: Can ordinary potatoes power a digital clock for more than 24 hours?

Variables: * Independent Variable – Potato * Dependent Variables – Clock, connection wires, copper and zinc plates

Materials Needed: * Digital Clock with 2 Wires * 6.25” Connecting Wire * Transparent Tape * 2 4” Copper Strips * 2 4” Zinc Strips * 2 Potatoes (Oranges worked too)

Background: How it works * A potato can be used as a battery by using strips of zinc and copper in the acidic juice of the potato to provide power to a digital clock. * With the zinc strip, the natural acid in the potato dissolves the zinc freeing electrons. * The copper wire uses the electrons that the zinc wire frees. * To obtain enough electrical current to power the clock, two potatoes must be used and they must be connected in a head-to-tail series.

Steps: 1. Put potatoes into containers to stabilize them. 2. Insert Zinc strip from the clock into the left potato. 3. Insert Copper end of the loose strip into the same potato, 2 cm apart and parallel to the Zinc strip. 4. Insert Zinc end of the loose strip into the right potato. 5. Insert Copper strip from the clock into the same potato, 2 cm apart and parallel to the Zinc strip. 6. Your clock should be running!

Data Table:

Results * Two large potatoes run the digital clock for more than 24 hours before the power fades. * Lemons, oranges and grapefruit also make good power sources. * Bananas have a very weak effect and do not run the digital clock for more than two hours.

Potato Clock Fun Facts: * When the strips