Potato Power: Investigating Energy Transfer in Grade 4

As part of our Grade 4 energy unit, we wanted students to explore how energy can be transferred and transformed in everyday materials. To spark curiosity, we posed a simple but surprising question:

Can a potato produce electricity and how can we measure the energy produced?

We kicked off the investigation with a short video to introduce the concept of a potato battery. Students were fascinated to learn that the humble potato could be part of a circuit.

The Challenge

Working in teams, students were presented with four challenges:

1. Connect one potato in a circuit and measure the voltage.

2. Test if one potato could light an LED or power a sound buzzer.

3. Connect two potatoes in a circuit and try again.

4. Connect three potatoes in a circuit and test for success.

   

Each group recorded their results on a challenge sheet where they tracked the voltage, LED light, and buzzer outcomes. They also drew a labeled model of one of their circuits to show their thinking.

And then came the final challenge: How many potatoes can we connect in series? As a class, we kept adding to the circuit until we reached our record — 22 potatoes connected together, producing 23.5 volts. The excitement in the room was electric (literally).

What Students Learned

Through trial and error, students quickly realized that a single potato does not generate enough energy to power most outputs. But by combining potatoes, they were able to see voltage increase and sometimes even light a bulb or sound a buzzer. It was pretty funny as the high pitch buzzer was so high in frequency that I couldn't hear! They thought that was hilarious.

The final challenge showed them the dramatic effect of connecting multiple cells in series. It was a clear, hands-on way to see that energy can be combined and scaled up.

This investigation tied directly into our big ideas about energy transfer:

• Energy can be stored in unexpected places.

• Circuits need more than one component to work effectively.

• Energy can be transferred from chemical energy (in the potato) into electrical energy and then into light or sound energy.

• Multiple cells connected in series can greatly increase voltage.

Why This Worked

This investigation worked because it was:

• Hands on: Students were building, testing, and revising their circuits in real time.

• Surprising: Potatoes are familiar, but their ability to produce power was a new idea that sparked curiosity.

• Connected: The activity linked directly to our energy unit, giving students a tangible example of how energy can move and change form.

Most importantly, it allowed students to experience science as inquiry. They were not just told that energy can be transferred — they saw it, measured it, and heard it buzz. And in the end, they witnessed just how powerful a classroom full of potatoes could be.