How to Make a Potato Battery Clock

This is a great lesson you can teach at home that will help kids learn about electricity, circuits, and chemistry. Chances are you already have most of what you need available. Let's get started!

Step 1: Things You Need

We used a kit to make this, but you can do this with stuff you have around the house. Here's what you'll need:

1. Potatoes
2. Insulated copper wires - 3
3. 2 sources of copper (i.e. pennies)
4. 2 sources of zinc (i.e. galvanized nails)
5. Digital clock with exposed wires for attachment

Step 2: Set Up Internal Battery Connection

We're going to make a battery that is made up of two galvanic cells connected in series. The first step is to prepare the "center" of the battery.

Take one penny and one nail and connect them with one of the wires. Make sure you are using the copper wire directly and not the insulation on the wire. We're using copper and zinc strips from our kit as shown in the picture.

Step 3: Set Up Rest of Circuit

You'll need your wires, digital clock, and remaining penny and nail for this step. Take one wire and connect one side to the nail and the other to the "negative" side of the clock. Take the other wire and connect one side to the penny and the other to the "positive" side of the clock.

Step 4: Get Your Potatoes Ready

That's it for this one.

Step 5: Assemble Your Potato Battery

Take your internal battery connection and place the nail in the left potato and the penny in the right potato as shown in the picture.

Next, take the nail from the negative lead on the clock and place it in the right potato, about a half-inch to inch away from the penny.

Finally take the penny from the positive lead and place it in the left potato as shown. Your digital clock should light up immediately.

Step 6: Here's Your Circuit Diagram

You made a battery from two galvanic cells and used it to power a digital clock. Nice work!

Step 7: What Else Can You Make a Battery With?

We just took tap water and used it to replace the potatoes. The clock lit up right away! What else can you use?

To learn more about the science behind what is going on here, check out our article on building a potato battery clock.