Fruit-Power Battery

Convert chemical energy from the acid in a lemon into electrical energy

Voltaic batteries of all shapes and sizes are objects that convert chemical energy into electrical energy. You probably use batteries to power your cell phone, iPod, or any number of wireless gadgets. But did you know that you can actually use chemical energy stored within a lemon to power a small LED light? It's true, and we'll show you exactly how in the Fruit-Power Battery experiment.

Materials

Four lemons (the bigger and juicier the better)
Four pennies
Five zinc-galvanized nails
Five sets of alligator clips
LED light
Kitchen knife

Experiment
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Reviews

Use a kitchen knife to cut a penny-sized slit in all four lemons.
Insert a penny halfway into each of the four slits that you cut.
Push a zinc-galvanized nail into each of the lemons, opposite the penny. Be sure you don’t let the nail and penny touch each other.
Connect all four lemons together with alligator clips. Each set of alligator clips should connect a nail with a penny.
Attach the two loose alligator clips to the LED light.
Check that out! The energy from the lemons lights up the LED.

How does it work?

Batteries are comprised of two different metals suspended in an acidic solution. With the Fruit-Power Battery, the two metals are zinc and copper. The zinc is in the galvanization of the nail, and the penny is actually copper-plated zinc. The acid comes from the citric acid inside the lemon.

The two metal components are electrodes, the parts of a battery where electrical current enters and leaves the battery. With a zinc and copper set-up, the current will flow out of the penny and into the nail. The electricity also passes through the acidic solution inside the lemon.

Once the Fruit-Power Battery is connected to the LED, you create a complete circuit. As the electrical current passes through the LED, it lights the LED, and passes back through all of the lemons.

WORKED FOR OUR LARGE HOMESCHOOL SCIENCE CLASS!

Kirsten - February 28, 2013

This user gave 4/5 stars

This is a great project and worked well for our class. A couple things to help have success:
Warm the lemons up by soaking them in hot water, that will make the juices flow, we made sure we had good juice flow by also lightly bruising them on the table.
Use pennies from 1979 and before for higher copper content.
IF the LED doesn't light up simply unhook from the light and turn the light around and try again, the current needs to flow in the correct direction to light it.
Darken your room. Or we used boxes turned on their sides to create a shadowed area.

No light for us

Payton - February 21, 2013

This user gave 3/5 stars

We were unable to get this experiment to work. We used the 5mm 1.8 volt LED light and even increased the number of lemons all the way up to 7! We checked the voltage of the circuit created from the lemons and it had ample voltage (3.9 v) but would still not light up the bulb. We verified that the bulb worked by using the an alligator clip & connecting it to two AA batteries which caused it to light up. We have no idea what went wrong....

the type of led light matters

Bam - January 12, 2013

This user gave 4/5 stars

I tried an old christmas light and it didn't work. So I used a 1.8 volt 5mm light from the source and it worked perfectly it stayed lite for over3 hours

The type of LED will make or break the experiment!!!!!!!

Julie - November 12, 2012

This user gave 4/5 stars

We first tried a readily available flashlight LED... too much resistance. Went to Radio Shack and got a 5mm Red 1.8volt LED and it worked great. We also made our own alligator clip cables by purchasing inexpensive clips at Menards and attaching them to wire from old Christmas lights.

Voltage for the LED light?

Brylyn - October 8, 2012

This user gave 4/5 stars

Anyone have a specific voltage that they used? I have 3.3 volts, but they don't seem to be lighting up. Thanks.

Fruit Power Battery

jumar - September 8, 2012

This user gave 5/5 stars

It really works. use a 5 peso coin because it is made up of 70% copper and 24.5% zinc and use a galvanized nail not other else and check the connection of your wires

Other Items

Keely - July 18, 2012

This user gave 4/5 stars

Can anyone tell me any other lights or item that would work in this circuit as well?

Lemon Battery Problem

Brooke - May 29, 2012

This user gave 5/5 stars

I am doing this in our science fair and for some reason it wont work. We have a voltage tester but in one lemon its in the 500`s and on two its in the 1400`s!! I dont know why. :l

to Liz again

Eva - April 26, 2012

This user gave 5/5 stars

and did you use galvanized nails or stainless nails, which would not work?

to Liz

Eva - April 25, 2012

This user gave 5/5 stars

Liz, did you try a different LED light?

Great simple experiment

Mafrlene Thomas - April 4, 2012

This user gave 5/5 stars

I am the Director of an afterschool program serving kids kindergarten through 5th grade. Each week I do a science experiment for "Really Really Wierd Science". This experiment was a segway into a month of electricity and the kids absolutely loved it. I do not try the experiments beforehand and am always concerned if they will work. No problems with this! I added a fiber optic to the bulb for some added effect. This week we made the battery...next week we make the bulb!

Lemon experiment

Liz - March 27, 2012

This user gave 5/5 stars

It didn't work. Used very juicy lemons, dirty pennies, clean pennies, more lemon in series. No lighting of the LED.

Steve's lemons

Pam Osborne - March 22, 2012

This user gave 5/5 stars

This guy is a genius resource of science fun. Lighting up leds in this way will also impart a lemon-fresh aroma to your kitchen, or wherever it is that your mom lets you set it up. Another good thing about this particular experiment: It won't shatter windows or spread sticky green slimy stuff all over everything in the house/garden/garage/your bedroom.
I should mention the music. It's so cheerful!

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