Science Buddies: "Ask an Expert"

Hello.
I'm working on this project, Dealing with Diabetes: The Road to Developing an Artificial Pancreas
https://www.sciencebuddies.org/science-f ... #procedure
Everything was going well until step 13. The water pump won't work when I put it in the vinegar bowl. I made sure all the Jumper wires are pushed firmly in the breadboard and that no exposed wires are touching. I also started the experiment over 3 times, and still the same thing; only it worked for about 6 seconds the 3rd time I tried. Please help me my project is due on tomorrow monday, dec. 5th, 2015
I'm pretty sure I followed all steps correctly. Please help me I don't know what to do.
Thank you very very much I'd appreciate your help.

sondous - The fact that the circuit seemed to work once, then stopped, is confusing. Sounds like wiring is correct, polarities are correct. What kind of pump, brand and model are you using? Perhaps that may be part of the intermittent observation. The FET is pretty robust, rated at 16 amps, so a small battery operated motor shouldn't be a problem. Tell us more if you can. What might you have done differently on the third try that seemed to get it to work?

Rick Marz

I really don't know, I just started everything over. And I ordered the exact same materials on the materials tab
And by the way, I kept trying over and over again until it worked and I got different trials but there was still some trials where it didn't work, but I kept trying, thank you.
I also want to ask, in the 'make it your own' tab, I tried doing the first variation by adding more vinegar to see if the pump would turn back on. Is it supposed to?? Because it wouldn't turn back on for me.
Thanks again

sondous - Adding more vinegar (acetic acid) would increase the ionization level of the solution and increase conductivity and should cause the current to flow to the motor. Possibly, a wire or component has loosened in the breadboard. Can you replace the motor with a 100Ω resistor and measure current through the motor loop? Try the motor on the 12 volt battery to make sure it is functioning.

Rick Marz

Thank you, Rick Marz.I didn't want to add more vinegar because it would change the numbers and I'd get confused on how much of the vinegar solution got neutralized. I don't think any wire or component was loosened because I checked them multiple times. I am going to. I already got a list of things to check from Amy Cowen. But I'm going to try that too. Thank you..

I am also doing same experiment & seeing similar problem.
Pump worked once & than it stopped.
We just realized that the MOSFET is very very hot to touch.
Can that be a problem?

Please reply ASAP.

Thanks
Mohag