PURPOSE: To illustrate magnetohydrodynamic forces.

DESCRIPTION: A shallow bowl of copper sulfate solution is placed in the (downward) magnetic field of a medium-strength horseshoe magnet. An electron current is created between the negative electrode band around the circumference of the bowl and the positive electrode at the center of the bowl. The resulting vxB force on the electrons creates counterclockwise rotation of the copper sulfate solution. Small pieces of paper are dropped onto the surface of the rotating liquid as an indicator.

Strangely, this device is described in a paper (see references) under the title "An Interesting Exhibit."


REFERENCES: (PIRA 5H30.50) See Demonstration Reference File for further information on magnetohydrodynamic devices and their applications.

EQUIPMENT: Magnetohydrodynamic device with copper sulfate solution, horseshoe magnet, and power supply.

SETUP TIME: 5 min.

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