Yet another demo: https://www.youtube.com/watch?v=9s9I8OI82Ag
What Happens When You Drop A Magnet Inside A Copper Tube [video]
21–30 of 125 posts
Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]
#22Earlier 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…
Iron is ferromagnetic, so the magnet will stick to the tube and not fall through.
Ah, but of course you are right. Then aluminum it is!
Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]
#23If magnet was not rotated when dropped through the tube, would it simply stick to one wall in case of slightest imbalance?
Copper isn't ferrous, magnets can't stick to it.
Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]
#24If magnet was not rotated when dropped through the tube, would it simply stick to one wall in case of slightest imbalance?
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.
Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]
#25If magnet was not rotated when dropped through the tube, would it simply stick to one wall in case of slightest imbalance?
No. Because copper isn't ferromagnetic, it will not be magnetized by the magnet, and consequently the magnet and the copper will not be attracted to each other. (In fact copper is diamagnetic, so it will actually slightly repel.)
Source: I am a magnet scientist.
Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]
#26I can only begin to imagine how much a piece of copper tubing that thick costs. That's a lot of copper.
The effect works just fine with thinner tubes and smaller magnets - I've done it using 15mm 'plumbing' copper pipes.
Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]
#27I can only begin to imagine how much a piece of copper tubing that thick costs. That's a lot of copper.
A kg is about $7 at the moment it seems, so suppose that's 5 kg then $35.
Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]
#28Yup, it's pretty cool. This was one of the most impressive demo's my physics professor did in our freshman physics class. The point is that as the magnet is falling through the copper tube it creates an electric current which then creates a magnetic field in the opposite direction of the magnet's movement. In other words, this is the practical application of the Right Hand Rule [1]. Two fun facts about it: first, if…
As long as it isn't a magnetizable substance like iron.
Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]
#29Where can you buy something like that. A magnet is around 150$, but I have no idea where to get a copper tube of that thickness.
It also works with a small neodymium magnet which can be bought for less than $1 and a small copper plumbing tube which costs about the same.
Re: What Happens When You Drop A Magnet Inside A Copper Tube [video]
#30Yup, 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…
You can also think of it as magnetic flux lines encountering "drag" as they pass through conductors. The limiting behavior of this view is in type II superconductors, which entirely "pin" flux lines -- they present an effectively infinite resistance to the movement of flux lines. That's why a magnet levitates over such a superconductor. [1] You can even image these "vortices" directly [2] [1] http://en.wikipedia.org/…
The levitation over a superconductor was the other cool demo that the professor did :).