Science Buddies: "Ask an Expert"

Hi, I am conducting the experiment for the "Electrolyte Challenge" and am consistently getting a reading of 0 no matter what liquid I put the conductance sensor in. I am completing the experiment using Gatorade, PowerAde, and Vitamin Water. After reading the FAQ I checked all of my connections and they are working, I made sure that the multimeter was set to 200m (milliamps), I checked the power on my battery and it is at 9V, I replaced the fuse, the wire is bare and there is no material collected on it. When I set the multimeter to a voltage setting a get a reading with the conductance sensor in the liquid. Please help, it's too late for me to switch projects.

MIssyTWhite370 - Check to make sure the multimeter leads are in the proper sockets. The BLACK lead is connected to COM and the RED lead is plugged into the VΩmA socket, NOT the 10ADC socket. As a matter of good practice, never switch a multimeter between ranges when connected to a circuit. To test the circuit, set the meter to 20VDC, reconnect to the circuit (without placing in the liquid) and there should be no reading until you 'short out' the sensor. The meter should then read 9 volts. With the ionized sport drinks, or orange juice, you should read between 20-60 mADC on the meter using the 200mADC range.

Rick Marz