Demonstrate that Water is Diamagnetic

This photograph shows the slight downward deflection of the surface of the water above a strong rare-earth magnet.  This is my version of the setup described by Conery and others in The Physics Teacher (v. 41, February 2003).  It was not easy to get the lighting angle "just right" so that the indentation about the magnet would be visible.

bulletRare earth magnet
bulletPlastic cat food lid
bulletFood coloring

I added just enough water to cover the bottom of the lid and enough food color so that the reflection would be from the upper surface.  Then the lid sits on top of the magnet.

This is a nice setup for occasional repeated use because the when the water evaporates the coloring remains in the lid and can be reused with the addition of water.

I tried viewing the reflection of many different lights and the only one that would work as shows was my kitchen ceiling light.  Even so, the angle of view was critical in order to "see" the very slight depression in the water's surface.

See Bill's message below for another way to detect the depression in the water.

Date Mon, 20 Jan 2003 121420 -0800 (PST)
From William Beaty <billb at eskimo dot com>
To: John Lahr
Subject Re Demonstration that water is diamagnetic


When I heard about this, I went and found a sunbeam in the kitchen and placed a bowl of water there. The water reflected a spot of light upon the ceiling. (I knew from "dishwashing experiments" that such a light spot is incredibly sensitive to tiny distortions of the surface, such as blowing upon it.) Sure enough, placing a magnet under the water caused a bright spot to form in the otherwise uniform reflection. This indicates that the magnet forms a depression. Hey, maybe with the right shape of magnet stack we could create a paraboloid with very long focal length.

Add an eyepiece and see if it functions as a telescope.

(((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))

William J. Beaty SCIENCE HOBBYIST website
EE/programmer/sci-exhibits amateur science, hobby projects, sci fair
Seattle, WA 206-789-0775 unusual phenomena, tesla coils, weird sci


Back to Diamagnetism

Back to Fun with Physics

Back to Fun with Science