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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]

#51

Post by sp332 »

IgorPartola wrote: post #2

Yup, it's pretty cool. This was one of the most impressive demo's my physics professor did in our freshman physics class. The point is that as the magnet is falling through the copper tube it creates an electric current which then creates a magnetic field in the opposite direction of the magnet's movement. In other words, this is the practical application of the Right Hand Rule [1]. Two fun facts about it: first, if…

I would wrap an electromagnet around the magnet in the tube, then turn on current to create a field in the opposite direction. Hm... If I pulse the field quickly, maybe it would even remove itself :)

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

#53

Post by Intermernet »

rbanffy wrote: post #43
IgorPartola wrote: post #30

Earlier quoted context omitted.

The levitation over a superconductor was the other cool demo that the professor did :).

Lucky kids. When I was in school, the only commercial superconductors were liquid Helium cooled Niobium-Titanium alloys, something not many classrooms could handle. ;-) Luckily, when I got to programming, we already had zeroes and ones. Imagine our predecessors who had to do it with uppercase o's and lowercase l's...

Zeroes and Ones? Luxury! In my day we couldn't afford the Ones, we had to make do with just Zeros...

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

#54

Post by vecter »

IgorPartola wrote: post #2

Yup, it's pretty cool. This was one of the most impressive demo's my physics professor did in our freshman physics class. The point is that as the magnet is falling through the copper tube it creates an electric current which then creates a magnetic field in the opposite direction of the magnet's movement. In other words, this is the practical application of the Right Hand Rule [1]. Two fun facts about it: first, if…

Technically, this has nothing to do with the Right Hand Rule. That is just a human convention to assign a positive and negative signs to a particular direction. Electromagnetism doesn't care about our silly human notations.

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

#55

Post by mjcohen »

rbanffy wrote: post #43
IgorPartola wrote: post #30

Earlier quoted context omitted.

The levitation over a superconductor was the other cool demo that the professor did :).

Lucky kids. When I was in school, the only commercial superconductors were liquid Helium cooled Niobium-Titanium alloys, something not many classrooms could handle. ;-) Luckily, when I got to programming, we already had zeroes and ones. Imagine our predecessors who had to do it with uppercase o's and lowercase l's...

Ha! When I was in school, we had to push the electrons around by hand! You kids had it easy!

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

#56

Post by noir_lord »

malandrew wrote: post #48
adsr wrote: post #27

Earlier quoted context omitted.

A kg is about $7 at the moment it seems, so suppose that's 5 kg then $35.

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's value (You often get 90-95% of its commodity value for recycling).

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

#58

Post by JakeStone »

mjcohen wrote: post #55
rbanffy wrote: post #43

Earlier quoted context omitted.

Lucky kids. When I was in school, the only commercial superconductors were liquid Helium cooled Niobium-Titanium alloys, something not many classrooms could handle. ;-) Luckily, when I got to programming, we already had zeroes and ones. Imagine our predecessors who had to do it with uppercase o's and lowercase l's...

Ha! When I was in school, we had to push the electrons around by hand! You kids had it easy!

You guys had electrons? We had to use scotch tape on a bunch of quarks and give them a half spin and then push them.

Uphill. Both ways.

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

#59

Post by lutusp »

lxmorj wrote: post #57

Hey, would it levitate there if the tube was spinning? It falls back and forth when he rotates it...

> Hey, would it levitate there if the tube was spinning?

If the tube were spinning, the magnet would begin spinning also, but it wouldn't levitate.

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

#60

Post by calinet6 »

vecter wrote: post #54
IgorPartola wrote: post #2

Yup, it's pretty cool. This was one of the most impressive demo's my physics professor did in our freshman physics class. The point is that as the magnet is falling through the copper tube it creates an electric current which then creates a magnetic field in the opposite direction of the magnet's movement. In other words, this is the practical application of the Right Hand Rule [1]. Two fun facts about it: first, if…

Technically, this has nothing to do with the Right Hand Rule. That is just a human convention to assign a positive and negative signs to a particular direction. Electromagnetism doesn't care about our silly human notations.

It does, however, exhibit the properties we use language to describe. There's a kernel of truth at the center of it.
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