skip graphical navigation
PBS KidsZOOM Home Back to Activity
Science Rocks!


Lemon Battery

next

your results

Sent in by:
Kendra of MO

This clock is citrus-powered!
Materials

Materials Needed


  • 2 lemons
  • 3 copper wires
  • 2 large paper clips
  • 2 pennies
  • a digital clock
  • scissors
  • knife

Instructions

Instructions


  1. Check with a grown-up before you begin.
  2. First, attach one of the paperclips to a wire.
  3. Then attach a penny to a second wire.
  4. Attach another penny to one end of the third wire, and a paperclip to the other end.


  1. Squeeze and roll two lemons to loosen the pulp inside.
  2. Make two small cuts in the skins of both lemons an inch or so apart.
  3. Put the paper clip that is attached to the wire and the penny into one of the cuts until you get to the juicy part of the lemon.
  4. Stick the penny into a hole in the other lemon.
  5. Put the other paper clip into the second hole of the lemon with the penny.
  6. Then put the last penny into the last open hole.


  1. Connect the free ends of the wires to the terminals of the digital clock.


  1. Watch how the lemons make enough electricity to turn the clock on. If you've hooked everything up and the clock isn't running, try switching the wires.


  1. Here's how this lemon battery works. There's a chemical reaction between the steel in the paper clip and the lemon juice. There's also a chemical reaction between the copper in the penny and the lemon juice. These two chemical reactions push electrons through the wires.
  2. Because the two metals are different, the electrons get pushed harder in one direction than the other. If the metals were the same, the push would be equal and no electrons would flow. The electrons flow in one direction around in a circle and then come back to the lemon battery. While they flow through the clock, they make it work. This flow is called electric current.
  3. This is hard to understand. So, if you need it explained to you again, be sure to talk to a parent or a teacher.


Now it's time to experiment. Do you think your lemon battery will still work if you change the lemons? Try cutting the lemons in half, or squeezing them and putting the wires in the lemon juice. Does your battery still work? Since lemon juice is an acid, think about how you can make batteries out of other acids, like orange juice or cola. Or see if your battery will work using a base, like soapy water. Choose one thing to change (that's the variable) and predict what you think will happen. Then test it and if you come up with some cool discoveries, send them to ZOOM.

Some of your Results

Jason, age 9 of Dover, PA wrote:
When I did the originl project I got about 6 or 7 volts. But when I scweesed all the jucie out of the lemons I got 10 or 11 volts.

Chase, age 12 of Garden City, MI wrote:
12 lemons lit a 3 led night light

Joe-Joe of Laguna Niguel, CA wrote:
It worked for a little while but then it stopped. what happened???

Julia, age 10 of Darien, CT wrote:
The lemon powered the clock! Cool!

Jewels, age 11 of Darien, CT wrote:
It didn't work unless I had really old pennies

Rana, age 9 of New York City, NY wrote:
it was amazing it was working i was very amazed

Alli, age 13 of Los Angeles wrote:
the lemon powered clock was not powered when we got copper pennies and large paperclips, where as the potato powered clock did work

Sophie, age 12 of Chandler, AZ wrote:
the first time we tried it did not work but after we left it in a ziplock bag over night and the next time we tried it powerd the clock.

Sara, age 11 of Chandler, AZ wrote:
The first time we tried it it didnt work but then we left the lemons in a ziplock bag over night the next day we tried it again then it powered up the clock!

Aditya, age 12 of Bhopal wrote:
when I do this I was shocked this works I connect this with a small bulb and bulb will shine

Zoie, age 9 of Wallins, KY wrote:
It worked you guys are the best you guys are smart.

Becca, age 11 of Lee's Summit, MO wrote:
I tried it the first time and it worked!! I also lit up a light bulb!! I did a potato battery too. I did a grape battery also!! I learned so much with this. I did it for my science fair project. People loved it.

Kate, age 13 of DC wrote:
I used this experiment with pears for my science project and it worked better

Asiah, age 12 of Middleburg, FL wrote:
i tried this project with my mom and cousins and grandpa exsept I did it with a light bulb it failed and we spent money on copper wire and 6 lemons and alot of work this project was for my 5th grade science fair but now im in 6th grade I luv to come to this website and do science projects!!!

Dagmar, age 13 of San Clemente, CA wrote:
I figured out why it didn't work! new pennies are NOT made of copper anymore. You need an older penny that is made of copper. Maybe that is why some of the other kids coudn't getit to work too??

Sophie, age 9 of Holt, MO wrote:
I used 3 potatoes. it worked! The first time it did not work because I did not have the metals in the right order. But, the second time it worked really nice!

Tori, age 11 of Dartmouth, MA wrote:
I don't get it!?! I tried it with my mom but it didn't work! I looked for a reason why but everything was exactly the way it was supposed to be! I was going to use it for my science fair project but now I have to look for a new one.!. I tried it so many ways but nothing happened!

Nathan, age 10 of Seattle, WA wrote:
A pear worked the best with 1. 06 volts

Emma, age 11 of Buxton, ME wrote:
It was cool. I powered a calculator, and I used it for my science fair project. Thanks!

Alan, age 14 of Dartmouth, MA wrote:
I tried it with zinc (found in nails, but I found pure zinc) and copper (a penny) first, and got 0. 5 volts. I tried it with many other metals, and the best combination was zinc and nickel, which gave me 0. 85 volts. I also tried steel nails (same effect as the paper clips) and pennies (because that was the original experiment). With my results in, I hooked up two lemon batteries in series for more voltage and was able to light a small LED. Pretty cool! I also tried lemons that were squeezed and were not, and the ones that were squeezed generated 50% more voltage. I am doing this for an independent study for science, and I think I learned quite a bit from this one experiment.

Danica, age 10 of Long Beach, CA wrote:
It was so cool! We used a pedometer instead of a clock though but it was still awsome! Im going to win the 4th grade science fair!

Justine, age 15 of Boston, MA wrote:
it worked. it works better with 3 lemons and potatoes too. you can use ungalvinized nails instead of paper clips. and you need pennys from before 1881 or else it wont work.

Steph,Sam,&Sara of New York, NY wrote:
well when I did it it the first time it didnt work until I noticed that something was connected wrong but then it worked

Omar, age 10 of Brooklyn, NY wrote:
I tried using limes, but it didn't work! I don't get it... what did I do wrong?

Jake, age 10 of New York, NY wrote:
Awesome! It was the best! It worked with a lightbulb. I did it 4 a science fair. Thank you ZOOMsci!

Zoom fan, age 11 of Alexandria, VA wrote:
It worked perfectly I had a project with the lemon clock and the potato clock and the potato clock won it was so awesome

Stephanie, age 11 of Topeka, KY wrote:
It worked well! I used oranges and it worked as well!

Jenny, age 10 of Chicago, IL wrote:
it worked a second. it was awsome.


not yet implemented