Electrolyte Multimeter Help

[mattsacct]

In setting up the multimeter for the Electrolyte challenge, the photo seems different than the instructions. The instructions say to attached the positive 9V wire (I am presuming is the red one) to one of the copper wires. The photo shows the red wire coming from the 9V battery going directly to the red multimeter wire and only the black wires attaching to both copper wires. I am confused. My project is due on Oct 25th and I have to do several trials. Thank you for your help.

[amyC]

Hi -- I checked in with one of our Experts who has helped extensively with this project, and there is a problem with the diagram on the Science Buddies site. We are going to correct this to avoid further confusion, but I hope this information will help you as you move ahead with your project.

The photo of the experiment showing all the wires and connectors is correct. The schematic diagram of the circuit need to be updated; the terminals on the digital voltmeter have to be reversed to work properly.

These are the steps you need to take:

a) Attach one of the free copper wires (either one) on the conductance sensor to the positive terminal of the 9-V battery, using the wire with one of the alligator clips.

b) Attach the other copper wire from the sensor to the negative POSITIVE terminal of the multimeter, using the other alligator clip.

c) Connect the negative terminal of the 9-V battery to the positive NEGATIVE terminal of the multimeter. (The completed circuit will look like the photo.)

Note that this is an open circuit because of the gap between the wires wrapped around the non-conducting tube. You will use the electrolytes in the solutions to close the circuit. The amount of current that flows is proportional to the electrolyte concentration.


Hope this helps!
Amy
Science Buddies

[mattsacct]

Thank you for your help, but the experiment is still not working. I have set up the wiring exactly the way it is in the photo and I can get 1 reading, but the fuse blows after each attempt. I got 1 gatorade reading. But I when I checked the next item I got all zeros, checked the fuse and it was blown. I changed the fuse, got 1 more reading and the fuse blows. I have used 3 different multimeters all with the same result. Any suggestions? Is there any other way to test electrolytes?

[KetchupSeedHD]

What setting should the multimeter be on voltage or amps and do i really need the battery because u saw sime videos where they dont use the battery they just stick the leads in the liquids

[rmarz]

KetchupSeedHD - This experiment is designed to use the 9 volt battery in series with the electrolyte and measure DC current. For most of the ionized drinks, the 200 mADC range is suggested. To get low level readings (microamps) when testing distilled or regular water, decrease the current setting to 2000 or 200 microamps. There may be similar electrolyte conductance experiments that utilize the ohmmeter function of the multimeter and read resistance of the electrolyte in ohms. In this setup, the meter provides test current from a battery internal to the meter so an external battery is not needed. Conductance is the reciprocal of Resistance. Because these readings are in 'ohms' the measured result must be converted to a conductance value by dividing the number '1' by the resistance (C=1/Ω). The result will be in 'Siemens'.

Rick Marz

[KetchupSeedHD]

rmarz-thank you