Science Buddies: "Ask an Expert"

[Note: I am posting this for a father/daughter. The project being worked on is:
https://www.sciencebuddies.org/science- ... p029.shtml
Veggie Power! Making Batteries from Fruits and Vegetables

The project is due tomorrow 4/16/09]

Problem: "she has properly established a two battery cell using a potato cut in
half. She has established and documented the current on each side and
together. Together, the voltage is slightly above 1.5 enough to power a
small light, watch, or calculator. The problem is she is having problems
connecting the wires to the target device in a way that powers the same
device. It seems as simple as connecting the positive lead from the battery
cell to the target device and doing the same on the negative side. But she
isn't seeing the devise work."



Amy
Science Buddies

Hi,
Assuming that the wiring is correct, it's possible that your veggie batteries are producing ample voltage but insufficient current. You can experiment with greater surface area of the electrodes (using more nails and or copper wires), cleaning the electrodes, electrode spacing, etc to try to produce more current. You can also try to configure multiple batteries in parallel, as in figure 2 in our project guide:
https://www.sciencebuddies.org/science- ... p029.shtml
Good luck! I hope I'm not too late.
Chris

Hi,
I agree with ChrisG that the potato battery might not be providing enough current. Try placing a current meter in the path from the battery to the target and measure the current.

Here's a good website that provides details on connecting measuring equipment to your circuit. I hope this helps!
http://www.allaboutcircuits.com/vol_6/chpt_2/4.html