Potato Battery: Understanding Chemical and Electrical Energy




Introduction: Potato Battery: Understanding Chemical and Electrical Energy

Did you know that you can power a lightbulb with just a potato or two? The chemical energy between the two metals is converted to electrical energy and creates a circuit with the help of the potato! This creates a small electrical charge that can be used to turn on a light.

This tutorial is a great example of how energy comes in many forms and how products use that energy in order to do work. The potato battery converts energy from chemical to electrical in order to allow the light bulb to work (benchmarks C and D).

Follow Faith Davis, Cheyenne Balzer, and Spencer White through this tutorial in order to make a battery out of a potato, and hopefully learn something about the use of energy and the technologies that use it!

Step 1: Gather Materials

  • 2 Potatoes (can be done with more if you want more power)
  • 2 pennies
  • 2 zinc-plated nails/screws (most screws are already zinc plated)
  • 3 pieces of copper wire
  • a small LED lightbulb or a voltmeter

Step 2: Strip Copper Wiring to Fit Penny

You need to make sure that you are stripping enough wire to wrap securely around the penny.

Step 3: Cut a Slit Into Each Potato

Each slit should be able to fit a penny, but it doesn't need to be exact because it can always be adjusted later!

Step 4: Wrap Penny With Wire and Put It in the Potato

The wire-wrapped-penny should fit snuggly into the slit you made earlier. This may take some adjusting and a little force to get the penny in right.

Step 5: Cut the Other End of the Copper Wire

On the side that the penny is not attached to, trim the wire to the length you want between the other potato plus an inch or two.

Step 6: Insert the Zinc-plated Screw Into the Potato

You want to leave enough of the screw out for the other end of the copper wire to wrap around, but still have the screw snug in the potato. Be sure that the screw doesn't go all the way through your potato! This step will take some force, and it's easier if you twist it in instead of trying to jam the screw in there.

Step 7: Wrap the Other End of the Copper Wire Around the Screw

Connect the two potatoes together with the wire going from the penny to the screw.

Step 8: Repeat Steps 2 - 4

Cut a new slit for a penny into the second potato that already has a screw and fit the new wire wrapped penny into that potato.

Tip: we cut all our wires to be around the same length overall to make things easier later on.

Step 9: Repeat Steps 6 - 7

Insert a screw to the potato that only has a penny, and attach a new wire to the screw.

Step 10: Review Connections

In the end, this is what the connections should look like. Look carefully at the sides of the potatoes. Each potato in the battery should have one zinc side (screw) and one copper side (penny) with wires attached.

Leave out two wires, one going to a penny and one to a screw. These wires will connect to the lightbulb or the voltmeter.

Tip: if you wanted to add more potatoes for more power, make sure to follow this pattern! Each potato should have one screw and one penny!

Step 11: Test Your Battery!

lay the exposed wire on the bottom of the bulb or to the prongs of the voltmeter to see your battery in action!

Tip: For only two potatoes, we found that it didn't produce enough power for a lightbulb. We ended up adding more potatoes after we discovered this.

Step 12: Reflect and Learn!

How it works:

A potato battery is a type of battery that is known as an electrochemical cell. The chemicals zinc and copper (in the screw and penny/wire) react with each other, which produces chemical energy. This chemical energy is converted to electric energy by a spontaneous electron transfer.

The potato acts as a buffer and an electrolyte for the two metals. This means that it separates the zinc and copper, forcing the electrons trying to get from one metal to the other to travel through the potato and form a circuit. The electrons are able to flow through the potato because it acts as an electrolyte. The two metals would still react if they just touched each other without the potato, but without the barrier and electrolyte, the energy released from the reaction wouldn't form a circuit, which is what gets the power to the light bulb.

When the two wires are attached to the bulb it completes this circuit, turning the light on!

Step 13: Our Learning Process

Problems we solved: Since we found that two batteries couldn't power our lightbulb, we were disappointed at the prospect of only showing the potato's energy through the voltmeter. To solve this, we decided to add more potatoes. When that didn't work we found an LED light bulb instead of the regular, incandescent one we initially were using. Finally, the light turned on with four potatoes and an efficient LED bulb, which is why we added the option to attach more potatoes to the instructions and why our materials say to use an LED bulb, even though our picture includes the incandescent.

Other ideas: We played around with a few ideas before deciding to make a potato-powered light bulb and explaining how and why it worked. We thought about making a small wind turbine or water turbine to produce electricity, and talk specifically about benchmark M or I but decided against it mainly because Spencer had some prior knowledge on how to make the potato battery work. Additionally, we wanted to try to use the potato to charge our phones but found that it would take far too many potatoes than we could afford. In the end, we were all happy with explaining energy in relation to benchmark C and D through the example of a potato battery.

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    7 weeks ago

    Good question 😊


    1 year ago

    Can a potato charge a cell phone? S Yang


    Reply 6 months ago

    yes mate you can charge your phone with potatoes, But the no of potatoes and requirements is not economical. and if any of the potatoes dry you have to find and replace them with a new potato. so overall you can buy a solar panel and make solar system more efficient.

    to generate 5V 2A you have to connect 500 potatoes 200gm of copper and zinc bunch of wire a lot of time to maintain.. better go with a solar panel and battery XD for a lot of discussion .


    Reply 1 year ago

    No, because the potato does not give off as much energy as a charger therefore the potato cannot charge a phone.


    Question 1 year ago

    Hi, i'm doing this project for science fair. I was wandering if you could tell me about the electricity behind the project. If you have any other background information you could share about the electricity or the science inside the potato. Thank you!


    1 year ago on Step 13

    I want to do the same " make a battery. " I'm learning the foundation of a created battery. Hope to show mine in the future. Bright sparks, we all are.


    Tip 2 years ago on Introduction

    Israeli researchers found that boiling the potatoes 8 minutes increases their output. I'd be interested to know if one boiled potato would power a LED.


    5 years ago

    First let me say thank you for this post. Although this has been done a few times with potatoes and a multitude of other food items, it is always great to see it again. This will pike the interest in some new students to try and make this and that is the beginning of more electronic students. So you never know, you could have started a whole new class full of new technicians...and that is always a great thing. Bravo sir, Bravo.

    DIY Hacks and How Tos

    Interesting. I wonder how this changes the taste of the potato.