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Science Rocks!

Lemon Battery II


your results

Sent in by:
Michelle of PA, Cassandra of WA, Christina of Ontario, Canada and Natalie

Electricity: charge it and pass it on!

Materials Needed

  • different fruits and veggies, including a lemon
  • 2 pennies
  • 2 large paper clips
  • 3 pieces of copper wire
  • scissors
  • knife
  • voltmeter
  • battery-operated digital clock
  • pencil and paper
  • lots of friends or family members



  1. Check with an adult before you begin. This activity has two parts and you'll need lots of friends or family members for the second part.
  2. Follow the directions to make a Lemon Battery. Be sure to get help from an adult if you're not allowed to use a knife.
  3. Make the same cuts in the other fruits and vegetables that you'll be comparing to the lemon. The ZOOMers tried apples, oranges, potatoes and bananas, but you could try anything from kiwis to kumquats.
  4. Draw a chart for the predictions you'll make and the results you'll record. Write the names of the fruits and vegetables in rows along the left side of the page. In columns along the top of your page write "predicted voltage" and "actual voltage".
  5. Make some predictions. Which fruits or vegetables will produce a current? Based on the voltage produced by the lemon battery, how much voltage do you think each will produce? Which will be the strongest? The weakest? Write your predictions on your chart.
  6. Now, it's time to test your fruits and veggies.
  7. Attach the copper wires, pennies and paper clips to each fruit or vegetable following the instructions for Lemon Battery. Attach each of your batteries to a digital clock. Which ones can power the clock? Indicate these fruits and vegetables on your chart.
  8. Now, find out how strong a current each produces. Instead of attaching your fruit and veggie batteries to the clock, attach them to the voltmeter. Record the voltage produced by each battery on your chart.
  9. How do your predictions compare to your results? Why do you think your results were the same or different? Does the clock require a certain voltage to run? Share your results with the scientific community of other ZOOMers.
  10. Now you're ready for the second part, pass it on! This is when you'll need to get help from your lab assistants (your friends and family members). Put away the voltmeter and reattach your clock to the fruit battery.
  11. Cut your lemon, or whatever kind of fruit you're using for your battery, in half so that the penny is in one half and the paper clip in the other half. The clock should go out, since you've just disconnected the circuit.
  12. Now hold one half of the fruit in one hand and your lab assistant's hand in the other. Have your lab assistant hold the other half of the fruit in his or her free hand. Does the clock light up again? It should, since you and your lab assistant are now part of a complete circuit.
  13. Make a prediction about how many people the current will flow through and still power the clock.
  14. Keep adding lab assistants to the circuit until the clock no longer runs. How do your results compare with your predictions? Is there anything you can do to increase the conductivity (the flow of current) in your circuit of lab assistants? Let us know if you come up with any interesting ideas or results.

Which of your batteries do you think will power a clock the longest? Make a prediction, try out your batteries and send your results to ZOOM. Can your battery outlast the potato battery made by Christina of Ontario? Hers lasted two whole weeks. That bunny better watch out!

Some of your Results

Emma, age 13 of Wanagnui, New Zealand wrote:
this worked really well I used it for my science fair. 2 lemons put out just about 2 volts and this powerd a digital watch but when I tried to power a 1. 5 volt lightbulb it woulndnt go and also when I tried a small clock it didnt go either. ialso tried a grapefruit and it put out just about as much as a grapefruit! do you know if a potatoe will work? thanks ZOOM!!!

Cynthia, age 12 wrote:
It worked, but I substituted the pennies with nickel and it worked much better It may not work if you do not have enough current Also, check if your positive and negative leads are in the correct order. The flat side of the LED must connect to the negative lead.

David, age 10 of Jacksonville, FL wrote:
i tried it the voltage was high, but there was no energy flow. It couldn't power up a light bulb can anyone tell me why?

Akshath, age 11 of St. Paul, MN wrote:
i tried a lemon and a potato and the lemon worked best. I did this for my science fair project. thanks zoom

Martina, age 16 of Braintree, MA wrote:
Mangos are way better than oranges for this project!

Sophie, age 9 of St. Louis, MO wrote:
I tried multiple times and the time it finally worked was when I used 2 lemons and an apple. Don't get mad at the clock. Add more juice!!!

Katie, age 14 of Princeton, KS wrote:
it was so cool. it lit a flashlight for 3 hours.

Jasmine, age 11 of Coalinga wrote:
it didn't work. I even tried a orange.

ZOOM Fan, age 14 of Simi Valley, CA wrote:
i tested multiple fruits, but the lemon didnt produce more energy!!! it turns out the kumquat did!!

Arron, age 4 of Mesquite, TX wrote:
i tried lemon grapefruit and a lime and ithink the leon or the lime or the grapefruit will conduct more electricty

Amy, age 11 of Taikoo, Hing Kong wrote:
IT WORKED! Its really fascinating how a lemon can power up suck things.. A grapefruit works too

Ella, age 14 of Rocklin, CA wrote:
it lasted for 3 days!!!

Branson, age 15 of UT wrote:
it was stupid like it worked for a minute then died! gosh

Danny, age 12 of Levittown, NY wrote:
It worked, The Voltage was 0. 74 and it powered a clock for a few days I compared a potato and lemon and the lemon was the best it lasted for a full 3 days while the potato only lasted 2

Mayur, age 10 of Guelph, ON wrote:
I tried a banana, grapefruit, apple, and potato. The apple was the best, then the grapefruit, then the banana, and finally the potato! I was really amazed!!!

Julia, age 10 of New Jersey wrote:
it dikdnt work like something was wrong with the terminals

Susue, age 11 of Oroville, CA wrote:
the lime worked the best not lemon

Fabio, age 16 of Ipswich wrote:
I first found out that the best combination of metals to use were Zinc and copper, this gave me a average reading of 0. 76. I then found that the best fruit was not the lemon but in fact it was the orange as it gave me a average reading of 0. 75 wheras the lemon was only 0. 72. I also changed how deep I put the zinc and copper in and found that this did affect the voltage, the best depth as 3cm it gave me a reading of 0. 77

Jerrod of Orangeburg, SC wrote:
the lemon work the best

Alex, age 11 of San Antonio, TX wrote:
the lemon conducted the most electricity

Frankie of Miami, FL wrote:
the lemon worked the best but how does the lemon and work better im still wondering

Sam, age 10 wrote:
i used orange, lemon and lime. Lemon was no. 1!!

Arthi, age 12 of Shalimar, FL wrote:
My project went spectacular! I also used this project in the science fair, thanks zoom!!!

Chris, age 15 of Chandler, AZ wrote:
The experiment was great!! The lemon produced the most volts per hour when I trialed it against a potato battery. Thanks pbs for the great idea and keep more coming!!

Jessica, age 8 of Culver City, CA wrote:
The lemon worked the best!!!

Jeaniree, age 11 wrote:
I tride using bananas, oranges, apple, but the lemon workt best!

Alana, age 12 of Miami, FL wrote:
I used limes, lemons, grapefruits, and oranges.(All citrus fruit) and I pradictied the lemon would produce the most and the lime did but they all measured more than 1 volt!!!

Sessalie, age 13 of Dunn, NC wrote:
I did it for the science fair with a kiwi potato dirt and an apple. The kiwi worked best and I won 1st place in the fair!!

Kirsten, age 13 of Detroit, MI wrote:
When I used oranges, like 2 volts came out of it. Not mili volts, volts!!! I also got shocked by it!!!

Lila, age 9 of Oakland, IA wrote:
I did it for my sience fair with a:Mango Potato Kiwi Lemon and a few more and actuly the smallest fruit (kiwi)had the most power.

not yet implemented