Let's Make a Lemon Battery

Hello Parents, Teachers, and children! Have you ever taken the time to ask yourselves how many items we use in our daily lives that use batteries? You would be amazed! The next question you might ask, “what is a battery”? There are many different types of batteries on the market today. We will look at an electrolytic cell called the “Lemon Battery”. This type of battery in its simplest form is a chemical reaction between two dissimilar metals (copper penny and the paperclip) in an electrolyte (the lemon juice). Those two dissimilar metals are called your Cathode (negative) and Anode (positive). See Figure 1 above.

When this chemical reaction happens, Electrons leave the Penny (Cathode) and gather on the Paperclip (Anode). Your Lemon Battery now has electrical energy stored inside ready to be used! Parents and Teachers, we would like to make this project as simple, inexpensive, and fun as possible for you and the children. So let us talk about what we will need for this project. Material checklist (also refer to picture 1 above on the left): 4-lemons 4-paper clips 4-pennies 5-wire with alligator clip on the ends (small speaker wire will work, just hard to connect to the electrodes) 1-1.2 volt LED (used a LED out of my son’s broken car) 1-digital volt meter (if you don’t have a voltmeter, you can skip to hooking up LED to test)

We do realize that not everyone will have access to a nice voltmeter, but it really helps you see what
voltage each cell (lemon) has in it when you make it into a battery. We also suggest buying some simple wires with alligator clamps on the ends. This makes life much easier when you are connecting your lemons. To see what an alligator clip looks like refer to picture 2 above, to the right.

Ok kids! What we want to do here is role the lemons on a flat surface. Place the lemon on a flat surface and put pressure with your hands on the lemon while rolling it back and forth. Once you roll the lemon, grab the lemon and squeeze it pretty hard. We don’t want to pop the lemon! What we are accomplishing with this step is releasing the juices inside the carpel section of the lemon. This is creating our electrolyte for our battery. Refer to figure 2 above.

***** Parents and Teachers do all the cutting on the Lemons! Do not let the children handle the knives!*****

Cut both ends of the lemons to allow our penny and paperclips to slide into the lemon. You will use one penny and paperclip on each lemon. Please refer to picture 3 above.

You will turn on your voltmeter and make sure it is set for Direct Current (DC).

Once you have your voltmeter set for DC, put your red lead from the voltmeter on the penny and the black lead on the paperclip. You should have somewhere around 1 volt. Please refer to picture 4 above.

You may have to adjust the range on the voltmeter if you are getting some strange readings. We also
would like to remind you that you do not have to have a voltmeter. You may use your LED as a test for current once you have all your batteries connected.

We are now going to use our alligator clips and connect the lemons together. Make sure that when you are connecting the batteries together that you connect the paperclip from the first lemon to the penny of the second lemon. Next, connect the paperclip of the second lemon to the penny of the third lemon. Now connect the paperclip of the third lemon to the penny of the fourth lemon.

After you have the lemons all connected in series (this is the type of circuit you just created with your batteries), put your voltmeter red lead on the penny of lemon one and the black lead on the paperclip of lemon four. You should get a reading around 4 volts. It may be a bit lower than 4 volts because not all lemons give you a true 1 volt. When you put the batteries in series like this you add the combined voltage of each lemon, which gives you around 4 volts. Refer to figure 3 for a drawing example and Picture 5 for a real world example

We are now going to use our alligator clips and connect the lemons together. Make sure that when you are connecting the batteries together that you connect the paperclip from the first lemon to the penny of the second lemon. Next, connect the paperclip of the second lemon to the penny of the third lemon. Now connect the paperclip of the third lemon to the penny of the fourth lemon.

After you have the lemons all connected in series (this is the type of circuit you just created with your batteries), put your voltmeter red lead on the penny of lemon one and the black lead on the paperclip of lemon four. You should get a reading around 4 volts. It may be a bit lower than 4 volts because not all lemons give you a true 1 volt. When you put the batteries in series like this you add the combined voltage of each lemon, which gives you around 4 volts. Refer to figure 3 for a drawing example and Picture 6 for a real world example

We hope that you all enjoyed such a simple and fun project. You probably never thought that your
lemons could produce electrical current to produce light. Just remember that you created a battery that generated almost 4 volts. Look online and see what else that you could power from your lemon batter. You could power small digital clocks and even calculators!

Always want to learn more and always be creative!!!!!