How to Make a Potato Clock?

It may seem impossible to use potatoes to generate electrical current, but it is actually quite easy to produce electrical charges using only a few potatoes and a few different types of metal. You can use this potato battery to power a clock for a short time in a science project or just for fun. Potato makeup conducts electricity but keeps the zinc ions separate in the nail and the copper ions, forcing the electrons to move from one to the other, generating electrical current. You can make a potato clock with two or more potatoes.

The potato clock is operated by converting chemical energy into electrical energy, which is then used to power a clock. Potatoes, in conjunction with zinc and copper strips (which act as electrodes), act as batteries. Most people don't know that this is possible, which is what makes it so interesting.

The energy is generated by the chemical change in zinc when it dissolves inside the mild phosphoric acid content of the potato. The energy doesn't come from the potato itself. What happens is that the zinc is oxidized inside the potato, that some of its electrons are exchanged with the potato acid in order to achieve a lower energy level, and that the energy released provides electrical power.

The potato clock is powered by acid, which reacts with a positive and negative electrode inside the spud. When the reaction occurs, the electron flows between the materials and generates an electrical current. The negative electrode, or anode, in a potato battery, is often made of zinc in the form of a galvanized nail. The positive electrode, or cathode, is often made of copper, which could be a penny.

Materials

• 2 large russet potatoes

• Sharp knife

• 3 pieces of copper wire

• 2 galvanized nails (nails coated in zinc)

• Alligator clips

• One small digital clock (the kind that takes a 1V circular battery)

Steps:

1. Remove the battery from the clock battery compartment. 

2. Notice how the positive (+) and negative-) (points of the battery went. 

3. The number of potatoes is one and two. 

4. Insert one nail in each of the potatoes. 

5. Insert one short piece of copper wire into each potato as far away as possible from the nail. 

6. Use an alligator clip to connect the copper wire in the number one potato to the positive (+) terminal in the battery compartment of the clock. 

7. Use an alligator clip to connect the potato number two nail to the negative-) (terminal in the clock battery compartment.

8. Use the third alligator clip to connect the potato one nail to the potato two copper wire and set the clock!

How does the Potato Clock Work?

The potato battery is an electrochemical battery, commonly referred to as an electrochemical cell. An electrochemical cell is a cell in which chemical energy is converted to electrical energy by spontaneous electron transfer. In the case of potatoes, the zinc in the nail reacts with the copper wire. Potato serves as a kind of barrier between zinc ions and copper ions. Zinc and copper ions would still react if they touched inside the potato, but it would only generate heat. Since the potato keeps them apart, the electron transfer has to take place over the copper wires of the circuit, which channel the energy into the clock. It's Presto! You've got the potato strength.

Potato Power

The potato battery to power the clock needs only a potato, two pennies, two galvanized nails, and three copper wires. When the zinc nail inserted into one end of the potato comes into contact with the mild phosphoric acid (H3PO4) inside the potato, it loses electrons during the reaction. Those electrons are then picked up by the penny inserted in the other end of the potato. The "rush" of electrons is an electric charge. While the potato battery produces just a few volts of electricity, researchers at the Hebrew University of Jerusalem revealed in 2013 that they have made considerable progress in creating a potato-based power supply that could be used to charge a mobile phone or laptop.