We are doing a science project and we don't know how to make a light bulb work with a potato. We have a copper wire, a potato, lemon juice, galvinazied nails, and pennies, an LED light, and a stand for the LED light. How do we make it work and do we need more materials?? PLEASE HELP THIS IS DUE 4-29-10!!

You may either not have enough voltage or enough current. I can't check until after April 15.

Ideally you need a voltmeter.

You need greater than 1.2 V. You need a LED with the lowest current you can find.

You may actually have to put your potatoes in series or parallel.

The separation of the electrodes (zinc/copper) will determine the current available as well as the cross-sectional areas within the lemon/potatoe of the electrodes in the direction of current flow.

You need about >1.2V and somewhere between probably 1 and 10 mA to light the LED brightly.

You can get a low value resistor like 10 ohms and measure the voltage and current of your cell.

You might also try a lemon.