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The Breakroom => The Water Cooler => Topic started by: 75Plus on November 28, 2013, 12:05:39 PM

Title: Is Copper Magnetic?
Post by: 75Plus on November 28, 2013, 12:05:39 PM
Before you answer check out this video!

http://www.chonday.com/Videos/magnetcopper1

Joe
Title: Re: Is Copper Magnetic?
Post by: Lew_Merrick_PE on November 28, 2013, 12:36:25 PM
Joe -- No, copper is not magnetic!  However, a magnet falling down a copper pipe generates a current within the copper that will oppose the field of the magnet providing the force opposing the drop.  You can do the same thing (though with less force involved) with aluminum.  I have used these principles to segregate materials from waste-stream processing for recovery.  Somewhere I have a WWI era book describing how to make this work with fairly high volumes of materials...
Title: Re: Is Copper Magnetic?
Post by: BronxFigs on November 28, 2013, 01:06:34 PM
Please tell me what kind of magnet was used.  Is this magnet one of those high-strength, super expensive Neo-whatever magnets that cost a fortune?  Fascinating video.



Frank
Title: Re: Is Copper Magnetic?
Post by: NeoTech on November 28, 2013, 01:38:19 PM
Its a neodymium magnet yes, and they arent that expensive, checkout supermagnete.de
Title: Re: Is Copper Magnetic?
Post by: JohnC on November 28, 2013, 03:52:51 PM
That is incredible!  So much so that I had to rush out to the shed to try it.  I used a piece of thick-walled copper tube about 20mm internal dia, and a 9mm dia neo magnet.  As I dropped the magnet down the tube, it slowed up as if falling through oil.  Fascinating!   :D

The magnet was one I got from ebay at not much cost, but is very powerful.
Title: Re: Is Copper Magnetic?
Post by: Bluechip on November 28, 2013, 04:13:12 PM
Whilst we are faffing about with magnets ....
 
     

 
Prof. Eric Laithwaite ... once went to one of his lectures .. much more amusing  for real ...  :)
 
Good bloke ...
 
 
Dave
Title: Re: Is Copper Magnetic?
Post by: z3t4 on November 28, 2013, 04:19:21 PM

Prof. Eric Laithwaite ...Good bloke ...
 
 
Dave

Eric Laithwaite: absolute freakin' legend! :beer:
Title: Re: Is Copper Magnetic?
Post by: 75Plus on November 28, 2013, 07:35:10 PM
I became aware of the reaction of copper in a magnetic field about 50 years ago. I had a precision beam scale that was dampened by a copper vane moving between two fixed magnets. It was almost as efficient as a hydraulically operated damper.
 
Title: Re: Is Copper Magnetic?
Post by: Dawai on November 28, 2013, 08:36:28 PM
Yes, slightly.. spinning a magnet close to a copper loop will heat it?

Water is slightly also magnetic. Diamagnetic? I think the word is? Water can exhibit anti-gravity "magnetic levitation" in the Lord Kelvins thunderstorm experiment.

     


The droplets "orbit" the coils as they transfer the electrical charge simulating anti-gravity.

To really see-learn some neat magnetic things, Magnetic universe, Leed Skalin?? Builder of Coral castle in Florida.

Title: Re: Is Copper Magnetic?
Post by: TLGriff on December 02, 2013, 08:00:25 PM
I used eddy current theory to build a magnetic damper for a scriber blade in a manufacturing fixture at work. The blade was oscillating as it was dragged across a plastic surface causing skips in the scribed line and the damper eliminated the oscillations. The damper was an aluminum disc attached to the scriber with a circular array of neodymium magnets in close proximity to it. As the magnets moved relative to the aluminum disc, they magnetized it, effectively damping the movement.

Tom
Title: Re: Is Copper Magnetic?
Post by: Meldonmech on December 07, 2013, 12:10:47 PM
Hi
                 You can pick up a one or two penny copper coin with a magnet, which is surprising until you discover that they are now copper plated steel. Can be a nice little party trick.
                                                                                          Cheers David