Where science meets magic and fun meets education!

Lenz's Law Demo

(Code: 24)

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Lenz's Law DemoIf you drop the little metal slug down the copper tube, it falls under the pull of gravity, and drops out at the bottom, just as you would expect.But take the second, apparently identical, slug; drop it down the tube, and hey presto! the slug travels down the tube extremely slowly. You can even see it's slow passage via the window in the side of the tube.It is a great magic trick, but the truth is just as amazing. The second slug is highly magnetic. Now Michael Faraday, the British physicist, discovered as long ago as 1831 that when you pushed a bar magnet into the opening within a copper coil, an electric current was produced within the coil. This is known as electromagnetic induction.The Russian physicist Heinrich Lenz observed that the direction of the induced current in a conductor is always such as to oppose the motion which produced it.So as the magnetic slug moves down the copper tube, a series of transient "eddy currents" are induced in the copper tube, and these currents will create a magnetic field that opposes the downward motion of the slug.CONTAINS MAGNETS. SUITABLE FOR CHILDREN 14 YEARS AND OVER

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Customer reviews
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 5/5
Great product. Well packaged and pleased to find this unusual item online.
 5/5
Just what I needed.
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 4/5
Lenz's Law: This could be improved with a smaller viewing port, so that the retardation effect is more pronounced.

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 5/5
 4/5
It works, although the buffer pads on the magnets / weights could be better secured, and had to be re-glued after a few demonstrations.
 4/5
The plastic elements quickly fell from the magnet, I had to glue them back. Still, the thing does what it's meant to. I'm very satisfied.
 4/5