Eddy currents defy gravity and let you float a magnet in midair. Think of eddy currents as brakes for magnets. Roller coasters use them to slow down fast-moving cars on tracks and in free-fall elevator-type rides.
Here’s what you need to do this activity:
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Find a thick piece of metal, like copper or aluminum to work with your neodymium magnets.
Materials:
- aluminum block (the thicker the better, although you can try a cookie sheet)
- neodymium disc magnets
When you have your parts, you can watch the video:
What’s going on? Here’s the basic idea: when a magnet moves near an object that conducts electricity (usually metal), it creates electric currents called eddy currents which start to flow in the conductor. These eddy currents create magnetic fields (electricity causes magnetism, remember?) in the opposite direction of the moving magnet, slowing an object down so it appears to float.
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LOL with the second video! Aurora, you are the best!
It depends on the hardware store, magnets are one of those things that some places will have and others will not. I also included order link on the main shopping list that you can click on that will take you straight to a page where you can buy them inexpensively.
It’s not an actual block, an aluminum cookie sheet will work just fine. Try to use what you have, you don’t have to actually go out and purchase a lot of these items. You want something that doesn’t stick to a magnet at room temperature
and will I find magnets at my hardware store
are there any other experiments that need a block of aluminium
We have a metal shop near my house, and they have a scrap metal bin that we can dig through. I would also look at places you may already have something like this, like an aluminum cookie sheet…?
Hi. Just wondering where you recommend we find a block of aluminum. Thanks.
Actually neither pure water nor sat conduct electricity, but salt water does! (Try the experiment in electrolytes here). I wonder what might happen if you try it in salt water?
Water is a conductor of electricity too. Why don’t magnets travel slower in water than non-magnets? Or do they?
Thanks for sharing your great idea!
Also: what happens if you drop them down a narrow copper pipe (one that’s barely bigger than the magnet itself)? I took a bunch of magnets to a hardware store and did my tests right there in the store and had a total blast baffling the guys that worked there with this idea.
Oh, and there should have an order link in Unit 11’s shopping list for KJ Magnetics online magnet store – that’s where I ordered mine that were used in the video.
Our local supplier did not carry neodymium magnets. When they tried a search, all the came up were earphones. So, we took an old set of earphones, smashed them and removed the magnets from each ear piece. Small, but works with aluminum cookie sheet.
WOW! Those magnets are STRONG … and they hurt fingers, too, as they smack together! Kids thought it was a blast just playing with the strength of those magnets (as I warned them to *stay away from the computer*! LOL!). What exactly would the magnets do to the computer?? Thanks!