This section contains pictures and descriptions of the MHD motor, static display and boat which I used in my presentation.

  • Use R = d/(A) where d is the distance the current travels
  • A is the cross sectional area of the material in which the current is traveling

    is the conductivity of the material

    In this case the material is a saturated salt water solution and:

  • d = 0.04 m is the distance between the electrodes
  • A = 0.0008 m2 is the area of an electrode = 22.6 (m)-1 for saturated salt water at 20 deg. Celsius
  • Carrying the calculation through to get R = 2.21 . Now use Ohms Law: V = IR where I = 3A (short-circuit current of a 9 volt battery) V = 6.64 volts So a 9 volt battery should do the job.
    • If the water is not saturated, which was the case with my project, you might want to put some more batteries in series. (I had 3 in series; on the heave side)
  • The Motor

    The Static Display

    The Boat was made out of a large piece of plastic Styrofoam and looked a bit like a barge.

    The motor was attached to the bottom by the copper rods (see above). The batteries and switching mechanism (to switch the polarity of the electrodes) were contained in a waterproof Tupperware container mounted on top of the barge.

    (Sorry, no picture due to technical difficulties. You're just going to have to imagine it.)

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