Science Smarts: Lemon battery

By PATTY ROOKS on November 11, 2021.

This is one of the most exciting times of the year for me! I am beginning to see Christmas decorations in the stores already. Perhaps it is too early for some of you, but whenever I see ornaments, tinsel and ESPECIALLY those outdoor ornaments, a smile creeps across my face.

One thing that I do not like is trying to figure out why my outdoor ornaments are not working. You see, electricity and I seem to disagree on occasion… if I am not getting zapped, it does not work and it takes me FOREVER to figure out. In order to brush up on my skills, I thought I would do a little circuits experiment this week.

Let’s get started!

Remember to ask an adult before doing this experiment.

Materials

• 4 lemons

• 4 pennies

• 4 galvanized nails

• Small led light

• Small piece of sandpaper

• 8 wires with alligator clips on (you may have to make these from the material at the hardware store)

• Multimeter (optional but

useful)

• Small kitchen knife

Procedure

• Take the nails and using the sandpaper, clean the clear coating off of them. It may take a little time to scrub this off, but it is important they are free of this coating.

• Have an adult help you cut one small slice (about 2cm long) in each of the lemons. Set aside.

• Take a lemon and push a penny about halfway down into the slit you just cut.

• Directly opposite the penny, push ONE nail into the lemon. Make sure they are far enough apart. You DO NOT want them to touch.

• Connect one alligator clip to the penny. Using the other side of the wire/alligator clip attach it to a nail on the second lemon.

• Repeat this order with the remaining lemons and alligator clips/wires.

• You will now have two alligator clips with nothing to connect to. Connect each alligator clip to ONE prong of the LED light.

• Watch what happens!

What is going on?

I hope your light bulb lit up! If it did not, you have my luck… do not despair though, often times this is what science is all about. We also need to learn to troubleshoot until we can find out what or where things went wrong. A multimeter is useful in this instance. You can remove the alligator clips anywhere in your circuit and connect it to the multimeter to see where the circuit is broken. Alternately, you can just move your lightbulb as well. I will also give you a hint – often times you just have the alligator clips backwards on the LED – switch them around.

I do not know about you, but I think it is pretty amazing that a simple piece of fruit can power a lightbulb! In this experiment, you are converting chemical energy to electrical energy.

Similar to a normal battery, your fruit battery also contains zinc (nail), copper (penny) and acid (in the lemon). The electrons flow out of the penny and into the nail through the acidic lemon juice. Once you connect the led, your circuit is complete (if it lights up)!

Keep an eye out for our VIRTUAL Family Science Olympics coming soon.

Patty Rooks, Senior Scientific Consultant PRAXIS, “Connecting Science To The Community”. Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. Address: #12 826 11 Street S. E., Medicine Hat, Alberta, T1A 1T7 Phone: 403-527-5365, email: praxis@praxismh.ca.

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