Electricity : Physics

I made a LEMON BATTERY today. I used these things:


  1. Six short electrical leads with crocodile clips at each end
  2. Five Lemons
  3. Five galvanized screws
  4. LEDs
  5. Five copper coins (1 cent US coins works)
  6. A sharp knife

First, make a cut in the lemon with the sharp knife. It should be a around 1 cm from the center. Put a copper coin in the hole you made. Do the same with the rest 4 Lemons. After that, put a galvanized screw on each of the 5 Lemons. If you turn the Lemon so that the copper coin is on the side, you should see a galvanized screw about 2 inches above from your work place. Remember that one end of the crocodile clip should be on the coin of a lemon and the other end should be on the screw of a different lemon. Put the Lemons in a circle. Squeeze the crocodile clips on one side of the Lemon – on the galvanized screw. Squeeze the other side on the other Lemon’s Copper coin. Do the same with the rest 4 Lemons. Put the rest 2 sides of crocodile clips on the LED. If it does not work, you can use the LED in the Snap Circuit kit. You will see that the LED lights up!

Doing the experiment
Zoomed in circuit
Lemon Battery Circuit
LED lights up!

I tried another experiment – It is the same, but it is with a POTATO instead of lemons! Do try the experiment out!

Potato Battery Circuit

Guess what? The experiment worked! I wondered how come. I also played by using different color LEDs and by changing the number of lemons and potatoes. It was a lot of fun! Let me share some of the observations I had.

  1. The LED in the Potato experiment glowed more than the LED in the lemon experiment.
  2. With the lemon experiment – if I did 1-3 lemons the LED did not glow. I had to put 4 to get a dim light and 5 lemons to get a little more glowing light.
  3. With the potato experiment – if I did 1 potato there was no light but if I did 2 or more there was a dim light or a glowing light.
  4. When I took out the screws and coins, their color was different! I think that happened because of the chemical reaction.
Experimenting and Playing with the Lemon and Potato Batteries
Lemon Potato Battery

I then joined both the circuits. I put an LED at 1 spot and 1 LED at another spot. I closed all the doors and put the lights OFF and this is a picture of then. I found this very interesting so I decided to do some more research. I researched about how this works and this is what I found out.

How it works

Physics is the study of just 2 things – Matter, and Energy.

Take a spoon. What do you think it is made up of?

That spoon is made up of a combination of different ELEMENTS. There are different types of MOLECULES in each element. Many ATOMS become a molecule.

Inside each ATOM, there are things called ELECTRONS. They circle the Nucleus, which is made up of Protons and Neutrons. Protons are Positive (+) and Electrons are Negative (-). Neutrons are none of these. They, together, in the circle form an Atom.

Electricity is the Electrons flowing and jumping. They get very excited and start moving to wherever they can.

What’s in a Battery?

In a Battery, there is a chemical reaction that happens. This makes the Electrons excited and jumpy and makes them flow. That produces electricity.

There are 3 parts inside a battery – Little cathode, A lot of electrolyte, and little anode. In the middle of electrolyte there is a sheet. When anode and electrolyte react, they produce jumpy electrons. These electrons are negative and so they want to go to a positive place. When cathode and electrolyte mix, they make a positive place to attract the electrons. They go through the wire and light up the bulb.

(Reference Image from Google)

How does it work with Lemons and Potatoes?

The Lemons/potatoes are the Electrolyte.

The anode is the galvanized screws which have Zinc coating.

The cathode is the Copper coins.

There is a chemical reaction inside and that is how the coins’ and screws’ color changes. Lemon has citric acid and Potato has Phosphoric acid. I think it can also work with Oranges because they also have Citric acid. It might work with Apple since it has malic acid. It might also work with tomatoes because it has Citric acid and Malic acid. I will experiment with a Multimeter to measure how much electricity gets produced in each. Stay tuned for my next post on this topic.

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