My son is in the 8th grade and is doing a science project on producing
electricity from fruits and vegetables. We have done the lemon
experiment with copper and zinc using a voltammeter. We would like to
know if anyone can help expand on this experiment. So far we can't get
any fruit to produce enough electricity to light a small lightbulb. We
have read many things about this experiment but they are either too
simple or they use terms we don't know (e.g. A-h current;1 k
resistors). Any ideas? Need info ASAP. Thanks.

Hi shmom and her son,

Speaking of electricity, ours went off just before I was ready to post
my answer (is that ironic or what?), so I've had to reconstruct it -
I'm sorry for the delay.

One fruit battery will not give off enough voltage to light an
incandescent lightbulb - think about how much heat a lightbulb gives
off to get some idea of how much current it takes to light it up. So
Mom, combine your home science lab with a lesson in business and set
up a little battery factory. Once you have half a dozen batteries
made, try lining them up in series and be sure to use a small
(flashlight) bulb - I hope you layed in a supply of lots of fruit!

FAQ about food batteries:
http://www.bluffton.edu/~bergerd/chem/food_batteries.html

Make electricity from fruit:
http://www.miniscience.com/projects/FruitElectricity/

MadSci Network: Chemistry:
http://www.madsci.org/posts/archives/nov99/943908416.Ch.r.html

Hands-On Museum:
http://www.aahom.org/pathways/Energy/4_PW_EN_ACT_FB.html

The Amazing Electric Lemon: Greater St. Louis Area Council:
http://www.usscouts.org/bbugle/bb0010/bbpackden.html

Fruit and Vegetable Clock:
http://www.physics.unl.edu/~fulcrum/resources/modules/fulcrum-energy-cell.pdf

Fruits and Vegetable Clock:
http://members.aol.com/ScienzFair/fruitbat.htm

Which Fruits or Vegetables Work Best to Make Batteries?:
http://www.ga.k12.pa.us/academics/ms/8th/scifair/scfair00/f8keeganp/f8keeganp.html

I hope this helps - please let me know how it goes! I better get this
posted before our lights go out again....hmmm, now where did I put
those lemons?

Good luck,
hummer

Search Strategy:
://www.google.ca/search?num=100&hl=en&ie=UTF-8&oe=UTF-8&as_qdr=all&q=light+bulb+%22fruit+battery%22&btnG=Google+Search&meta=

Terms Used:
light bulb 
"fruit battery"

Here is a simple experiment to create a battery from a potato:

http://www.quantumscientific.com/pclock.html

Because of their high acid content, lemon batteries likely produce
more power. Making the zinc and copper strips closer together and
bigger = more surface area will increase the available current. Make
sure the strips don't touch each other. Fruit batteries in series will
give more voltage which is likely necessary if the bulb is rated 2
volts or more. I suggest an LED = light emitting diode. You may be
able to remove one or more from junked electronic stuff. Alternately
they are likely about $2 at radio shack. Be sure the voltage rating is
2 volts or less. Old ones light red or green but other colors are
available now. You will need at least 2 fruit batteries in series to
light an LED, but it will probably light brightly for an hour and
dimly for several hours instead of the minutes you can expect from an
ordinary bulb = incadescent. For both LEDs and incadescent look for a
current rating of 0.11 amps = 110 ma or less or you will need a series
parallel array of fruit batteries. You probably don't need a series
resistor for any kind of LED as the fruit batteries have several ohms
internal resistance. If you do use one choose 10 ohms or less or you
can use a small incadescent bulb as a resistor.   Neil