Science Buddies: "Ask an Expert"

Hi!

Did the coin battery experiment with my son today, got voltage on all but no current. I did it alone being very precise and still no current. The first time we cleaned the coins with dishsoap, the second time I cleaned them with 91% rubbing alcohol (saw this as a suggestion in another post on the experiment). I made sure the squares weren't sopping wet and didn't touch each other. Any ideas of what we're doing wrong?

dscooby279 - If you are generating voltage on each cell, you are also generating current, albeit, possibly quite small. How are you attempting to measure current? My guess is that you have a incorrect current setting on your multimeter. This project will not generate very much current, so I suggest that you use a fairly low level setting, maybe starting at 2 mA (may be marked as 2000 uA on your meter) and see if you get a current reading at that level. Adjust your meter accordingly. Your black meter lead should be plugged into the COM socket, and your red lead into the VΩmA socket (not the 10ADC socket). Try this and let us know if you solve the mystery.

Rick Marz