1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: A real life problem, just for fun

  1. Nov 11, 2007 #1
    1. The problem statement, all variables and given/known data

    Around one of our buildings we have an "ant channel" of roughly square cross section (say 20 cm x 20 cm) with fish in it to control the mosquito larvae. The surface of the water carries particles giving a good indication of any surface movement.

    Late one afternoon we observed the surface moving relatively quickly (say 3 cm/s). Suspecting a leak we followed the moving surface water and were amazed to find that the moving surface gave way abruptly to a still surface. Watching a little longer we observed that the interface between moving and still areas of the surface was itself moving -- at about half the velocity of the moving surface.

    It appeared as if there was a discontinuity in the flow of water.

    2. Relevant equations


    3. The attempt at a solution

    I think I can explain the phenomenon. If no one gets it, I'll give clues.
  2. jcsd
  3. Nov 11, 2007 #2
    Hm. I'm not sure. But can I hazard a guess? There's a change in the depth of the water?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook