January 16, 2010 Issue

Physics To Go 89 - Floating frog/ferrofluid

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Physics in Your World

The Real Levitation image
image credit: Andre Geim; image source; additional image

The Real Levitation

This frog defies gravity with diamagnetic levitation. Many materials that we ordinarily think of as non-magnetic can be manipulated using magnetism.

It's easy to show that grapes are diamagnetic--just see this Exploratorium snack. For an explanation of diamagnetism, see the text at the end of the snack.

You may have seen the Levitron, the spinning and levitating top, in a physics classroom before. Read about how it works here.

(This feature was updated on August 18, 2013.)

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Physics at Home

Exploratorium: Snacks about Magnetism

Try any of these experiments from the Exploratorium to learn more about magnetism. Many of them use household items; some equipment may be more difficult to find. Have an adult help you.

You might also want to try making a ferrofluid like the ones in the From Physics Research feature above. Again, get help from an adult.


From Physics Research

Ferrofluids image
image credit: Gregory F. Maxwell; image source; larger image


Ferrofluids are made of tiny magnetic particles suspended in a liquid. In this image, the ferrofluid pushes above a surface layer of oil and forms spikes along the magnetic field lines of a magnet underneath.

For more images of ferrofluids, check out this picture and the archived Physics to Go feature, "Ferrofluid Fun."

Worth a Look

2000 years of magnetism in 40 minutes

Check out 2000 years of magnetism in 40 minutes for an overview of magnetism with an eye toward the history. The lecture is a quick read and includes pictures of magnetism demonstrations.

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