The aluminum pie tin experiment - Using a stronger magnet !

Already an expert on magnets? Then skip to the "aluminum pie tin experiment" at 1:17 .

Which materials are strongly attracted to a magnet? A cow magnet is used to try to pickup a rubber comb, a nail, a brass medallion, a piece of aluminum, plastic, copper pennies, a screwdriver, a piece of steel, some nickels (Canadian and United States), wooden dowels, paper clips, a washer and a brass object. Can you predict which objects the magnet will pick up? (Turn down the volume, and make your predictions as the magnet approaches each object.)

It is common knowledge that magnets can pick up most materials made of iron. Less well known is that nickel and cobalt are also strongly attracted to magnets (like iron, they are ferromagnetic).

What if we used a stronger magnet? A neodymium magnet still isn't able to pick up a piece of aluminum, but it can interact with it (see video clip) ! As the strong magnet moves near the surface of the aluminum pie tin, it pushes against the electrons in the metal, causing eddy currents. Those currents create their own magnetic fields which interact with the magnet.

Category:

Education

Tags:

• Experiments
• Magnets
• Electricity
• Magnetism
• Science
• Physics
• Demonstration
• Aluminum
• Iron
• Steel
• Copper
• Nickel

[rogerscottq]

There is a link to the so-called "master magnet" on Robert Nelson's site. A huge repository of information, patents, experiments and non-mainstream research. Evidently links cannot be posted here but the site address is rex research dot com

[ElectricVentures]

@rogerscottq Yep, YouTube bans URLs in comments.  Although your link didn't use the term "hooper magnet", the "master magnet" appears to use alternating current and coils of wire to induce powerful eddy currents in nearby metals. The result can be repulsion (as done in this experiment with the aluminum pie tin and eddy current separation devices) or attraction. A wikipedia article on Eddy Currents describes the geometries wish can push a conductor towards an electromagnet.

[rogerscottq]

Isn't water a polar molecule? Put the magnet in a dish of water and put it in the freezer and observe the pattern of the water. I've done this but wasn't sure that the pattern wasn't due merely to the freezing process around a warmer body. How about putting foodcoloring in the water and just move the magnet under the bowl and see what happens? I was hoping to find on youtube a demo of the Hooper magnet which supposedly can pick up any metal. Not.

[ElectricVentures]

@rogerscottq Your suggested experiments sound interesting. Why don't you experiment further and let us know what you find? I've heard of "hopper magnets" that are used to remove ferrous contaminants from various materials, but have never heard of "hooper magnets that can pick up any metal. The latter sounds like science fiction. What is the source of your information?

[roidroid]

Today on youtube i've seen a lot of demonstrations of eddy currents involving things suspended in water.  I worry that they are not clearly showing that the pie-tin isn't just being moved by the wind from your hand.

Don't get me wrong, i do understand what's going on. I just think that to be clear you should try to rotate the aluminium-pie-tin with a standard (non magnetic) piece of metal too, to show that it's not all wind effect.

[ElectricVentures]

@roidroid Indeed, the wind from ones hand will move the pie-tin somewhat, but the effect of the magnet is MUCH greater. Viewers should try the experiment for themselves. Seeing the video will help one remember the effect. Doing the experiment will help one understand it.

[rogerscottq]

Then the specific page appended would be: slash mr magnet slash mr magnet dot htm

Remove the spaces and replash slash with an actual slash and dot with a dot.