“Potato clock” experiment
How to make a potato battery for a clock
If you wind up on a desert island or in the midst of a natural disaster, knowing what time it is just might help you keep your bearings! Have a look at this cool experiment you can do at home!
Don’t eat any foodstuffs involved in the experiment.
Reagents and equipment:
- 2 potatoes;
- copper wire;
- zinc wire (you can use a zinc-coated nail);
- crocodile clip wires;
- electronic clock.
Insert one copper and one zinc wire into each potato. Use one set of crocodile clip wires to connect the zinc wire of one potato to the copper wire of the other potato. Use the remaining crocodile clip wires to connect the zinc wire to the “–“ terminal and the copper wire to the “+” terminal. The clock should work!
Fruit and vegetables can fuel not only living beings, but electronic devices too! To obtain electricity from them, we need a few pieces of copper and zinc wire (a zinc-plated nail can substitute for the latter). If we place these wires in an electrolytic medium (a substance that, once dissolved, can conduct electric current), by closing the circuit, such as in a household multimeter, we receive the value of the voltage of this “battery.”
Besides starch, potatoes contain a large amount of various soluble salts and acids, which serve as electrolyte. The zinc wire in our “battery” serves as a negative electrode (anode), and the copper wire serves as a positive electrode (cathode). In this improvised battery, an oxidation reaction takes place on the anode, and a reduction reaction takes place on the cathode. And if we close this circuit, an electric current will pass through it, powering the clock!
Zn – 2е⁻ = Zn²⁺
Cu²⁺ + 2е⁻ = Cu
Zn + Cu²⁺ = Zn²⁺ + Cu
You can use bananas, apples, oranges, lemons and many other kinds of food as the “battery.” Try and experiment – science is a wonderful thing!