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What Happens When You Drop A Magnet Inside A Copper Tube [video]

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Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]

#101

Post by 72deluxe »

salgernon wrote: post #11
IgorPartola wrote: post #5

Earlier quoted context omitted.

Fingers will also be pinched and possibly broken.

The latch on our clothes dryer broke; the door would no longer snug up and maintain the seal or necessary pressure for the safety switch. I now have a 2x2x1" rare earth magnet holding the door shut against the dryer frame. Its strong enough to keep the door snug, but I can still open the dryer door with a good tug. I'm not sure why I had a 2x2x1" neodymium magnet laying around, but I'm glad I did.

It is interesting that with the neodymium magnets being rare earth materials and apparent limits being placed on their mining/import/export etc., the price of them has sky-rocketed. There was a time when all the bass cabinets for bass players were getting smaller and smaller and lighter and lighter thanks to these magnets because it meant you could have a smaller speaker driver (hence less weight) but now they're having to resort to the heavier speakers again.

A shame really! I never did buy any light cabinets but always wish I had! At least Class D amplifiers are doing the rounds and so massive wattage amplifiers are now tiny and lightweight.

Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]

#102

Post by 72deluxe »

noir_lord wrote: post #56
malandrew wrote: post #48

Earlier quoted context omitted.

That's it? I was under the impression that copper was far more expensive and is the reason why expresso machines are as expensive as they are.

Copper compared to many metals isn't particular expensive per KG, it is just relatively expensive in the class of metals that we use a crapload of (for example aluminimum is around $1.8 per KG) it is still much cheaper than tin at ~$22. The main reason that copper is so valuable is it has so many uses and is very easily recycled(I saw an estimate that said 80% of all the copper ever mined is still in use) so holds it…

Here in the UK there is constant copper theft going on. The church up the road here had their roof pinched 3 times in 6 months. But it is good that if you have new heating (with a combi boiler) and your condenser boiler taken out, that massive water tank you had in the loft to hold water now suddenly turns into money!

Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]

#103

Post by 72deluxe »

evan_ wrote: post #15
IgorPartola wrote: post #13

Earlier quoted context omitted.

You really don't need anything as fancy. A small magnet and a narrow aluminum tube will do just fine. It won't be quite as impressive, but drop a pebble from the same height not through the tube and watch the delay for the magnet dropping. A four foot length of tube about 1/2 to 3/4 inch in diameter would do nicely. Edit: try cast iron if you must have a big pipe. It's likely to be much cheaper. The thickness shouldn…

it's a less impressive demo if the pipe is made out of something ferrous, like cast iron.

But it would be amusing!

"Watch this!" ....CLINK

Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]

#104

Post by dm2 »

malandrew wrote: post #8

I can only begin to imagine how much a piece of copper tubing that thick costs. That's a lot of copper.

This piece is close: http://www.amazonsupply.com/dp/B003JU1FBG/ref=sp_dp_g2c_asin

6.5 inch outer, 5.5 inner, 12 inches tall (twice what the video shows) for only $700. So I'd say $300 would be a good estimate of what you can get that piece of copper for.

That magnet is also probably pretty expensive, that's a big one.

Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]

#108

Post by chrissyb »

aunty_helen wrote: post #82
dublinben wrote: post #40

Original link: https://www.youtube.com/watch?v=keMpUaoA3Tg This digg page is blogspam.

The problem with the youtube link however is that any video with 'magnet' in the title brings you uncomfortably close to thousands of youtube nutters posting about perpetual motion machines.

Fantastic point.

Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]

#109

Post by chrissyb »

plq wrote: post #52

Another cool physics experiment: What happens when you wring out a wet cloth in space? Here's the answer: http://youtube.com/watch?v=KFPvdNbftOY

As much as i like that video nothing will top his special version of Bowie - Space Oddity

This might also pique you interest http://www.youtube.com/watch?v=_dQJBBklpQQ

Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]

#110

Post by shawabawa3 »

dfbrown wrote: post #42
martinvol wrote: post #24

Earlier quoted context omitted.

I can't clearly remember my psychics class, But I think I'd fall a bit faster, as the movement through the pipe is considerable as well.

I don't think the spinning should have any effect on the speed. Only the vertical movement would create eddy currents. It could be he does it to keep the magnet stable as it falls (like spin on a football).

In the last drop he doesn't spin it and it seems to fall at the same speed, it also wobbles and hits the side, so I think you're right
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