Science Buddies: "Ask an Expert"

Hi i am doing the electrolyte challenge project from science buddies and am having a problem. I have attached all the wires and and made a conductance sensor, but for some reason, no matter which substance i dip it in the multimeter reads zero. This is wierd because it just randomly stopped reading after I tested a few drinks for the project. I was also wondering what the decimals on the multimeter mean and how do i convert that into electrolytes...or IS that decimal the number i should use in my data table?
Thanks!!!

I'm sorry to hear you're having problems with this experiment. I'll give you a few things to check.

1. Make sure your 9V battery still works
2. Make sure the connections to the battery are tight
3. Make sure your multimeter is connected correctly. The + side of the battery must be connected to the + terminal on the multimeter. If is connected to the - terminal, the meter will most likely show no reading. Different meters react differently to being connected wrong, but this is the most common affect.
4. Make sure the copper wires on you plastic tube have not been covered with some kind of gook that would prevent electrons from moving from the liquid to the copper wire
5. Make sure you multimeter is set on an ampere range that is sensitive enough to measure the very small currents in this experiment. The instructions suggest a range that will allow you to measure a current as small as 200 micro-amperes.

I can't answer your question about the decimals on your multimeter. That depends on the specific model of your meter. I recommend you refer to the users manual that came with your meter.

You will CALCULATE the conductance using the formula in the experiment description. You will do this by converting the measured amperes and voltage to conductance.

I hope this helps.

Good luck.

Thank you so much!! I will try the project again doing everything exactly as you said. Hopefully it will work
right this time