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How does water volume affect electrical resistance?

  1. Nov 27, 2014 #1
    Hi, I've had an idea for a school physics project but I'm not sure if it will work.
    I want to measure the volume of water in a fixed shape container by passing an electrical current though it and monitoring how the resistance changes (with a potential divider circuit). My idea is that if I connect two electrodes at the opposite ends of the bottom of the container and then add more water to the container, the resistance would drop. I got this from how a thicker wire has less resistance than a thinner wire. However, I'm guessing that water doesn't work in the same way as metal wire so I would really value your opinions on how you think this will or won't work.
  2. jcsd
  3. Nov 27, 2014 #2


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    Pure water doesn't conduct electricity very well but otherwise it should work. It might not be very linear if your container is very tall.

    Edit: I forgot to add that if you use a potential divider circuit one of the electrodes will be at a higher voltage than the other. This may result in electroplating effects (eg one electrode dissolves). This is unlikely to be a problem if you only need it to work for few days.
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