Magnets

[Johnny Pneumatic]

http://www.dansdata.com/images/ecmags/conering560.jpg


Is the ring floating?

[scribble]

Sheesh, how the hell would you tell? Looks like it's just stuck on that cone from this angle. Show me another one.

[cbish]

Looks like a bad photoshop job to me!:p

[Johnny Pneumatic]

from here http://www.dansdata.com/magnets2.htm

[scribble]

From your quoted site:


It'll resist until it passes the tip and then click into place, like this. This feels much the same as forcing a ring magnet onto a rod magnet, but the cone-and-ring combo lets you do a trick


It's not floating, and he says so himself. It's stuck on there. There's a lot of fun you can have playing with magnets. Or so it seems to me - my parents were cheap bastards.

Further note: have you ever tried the ring-magnet onto rod-magnet trick he's talking about? You can shoot those rings pretty good that way with a strong enugh magnet. Switching to a cone only means you don't have to hold the ring in the sweet spot yourself (because it can't slip back).

[teddosan]

The magnet is not floating. Go back and read the website. They make no claim that the magnet is floating...

[TillEulenspiegel]

RE magnets are no big deal anymore.
If you want to see somthing spooky look up superconductor Maglev. The "superconductors are not even conducting metal but ceramics , sounds like Woo-Woo but it's not.



Edit to add link:http://hyperphysics.phy-astr.gsu.edu/hbase/solids/maglev.html

[scribble]

Originally posted by TillEulenspiegel
Edit to add link:http://hyperphysics.phy-astr.gsu.edu/hbase/solids/maglev.html [/B]

Nice explanation at the link, too. Wish I had one of those to play with instead of the RE magnets...

[Johnny Pneumatic]

I'm buying one of these
http://www.dansdata.com/images/ecmags/monster640.jpg

[EdipisReks]

www.dansdata.com is a GREAT website, and dan himself is a skeptic and has been involved in debunking devices like "free energy machines" and such in Australia.

[EdipisReks]

bewareofdogmas, please remove the pictures and rehost them yourself. stealing other peoples bandwidith is a no-no.

[Quixote]

Anybody can levitate magnets. But levitating frogs, that's impressive.

http://www.hfml.sci.kun.nl/froglev.html

[Brian]

Originally posted by bewareofdogmas
I'm buying one of these
http://www.dansdata.com/images/ecmags/monster640.jpg

If that puppy is neodymium, try not to lose any fingers!

[scribble]

Originally posted by Brian

If that puppy is neodymium, try not to lose any fingers!

The author of the website mentions this too, but it really can't be stressed enough. These aren't your momma's fridge magnets, by a longshot.

[davidhorman]

I'd like to build one of those magnetic "rail gun" things. X is a magnet and O is a ball bearing:

O XO XO XO XO XO XO XO XO

You push the leftmost ball against the nearest magnet. It imparts it's momentum to the ball on the other side, which leaves the magnet and moves toward the next, gaining momentum from the magnetic attraction. And so on, and so forth, until the ball at the end leaves at high velocity.

Found it on a website, can't remember where.

David

[scribble]

Hrm... the railguns I'm familiar with - here's an example (I put "railgun" into google and hit "I'm feeling lucky.")

http://www.railgun.org/

...don't work like that at all. In fact, unless you're talking about some rapidly-switched electromagnets, I can't see how the device you describe could work to add more force than you could with a single magnet (like in the above cone example).

(Edited to add: in fact, what your proposing there looks suspiciously like a perpetual motion machine...)


Why are there no magnets around the rails? -
The magnetic field in a true railgun is induced by the current in the rails, not by the application of exterior field.


There's no magnets in your typical railgun.

[richardm]

I suppose you've all encountered the Levitron (http://www.levitron.com/) ?

I got one of these for Christmas. It really is amazing :)

[davidhorman]

...don't work like that at all.

Google to the rescue - I knew railgun wasn't the right word. I was thinking of Gauss Rifle (http://www.scitoys.com/scitoys/scitoys/magnets/gauss.html).

David

[scribble]

Thanks, David-

Gauss rifles are fascinating too. I always thought they worked using electromagnets, not "plain-old" magnets.

That's really fascinating. It took me a little while to see why it's not a perpetual motion machine. Tell me if I'm right - in layman's terms, you'd say that keeping the marble 5/8th of an inch fromt he square magnet is *stored energy?* int he sense that that ball wants to "fall" onto the magnet?

[Johnny Pneumatic]

Originally posted by Brian


If that puppy is neodymium, try not to lose any fingers!



Yeah... http://www.wondermagnet.com/crush.html Ouch!

info on the disc

Composition: NdFeB
Shape: disc
Coating: Nickel Plate
Dimensions: 2" dia X 1" thick
Br max: 12,100 Gauss
Bh Max: 35 MGOe

Wow!

[Hamish]

Originally posted by scribble
Thanks, David-

Gauss rifles are fascinating too. I always thought they worked using electromagnets, not "plain-old" magnets.

That's really fascinating. It took me a little while to see why it's not a perpetual motion machine. Tell me if I'm right - in layman's terms, you'd say that keeping the marble 5/8th of an inch fromt he square magnet is *stored energy?* int he sense that that ball wants to "fall" onto the magnet?

I was sceptical when I saw David's first post. Of course there should have been two ball bearings after each magnet. There is only energy in the system if for each magnet there is a ball bearing not in the "ground state" (lowest possible potential energy). By spacing the ball bearings such that each is held in place by the magnet behind but not touching it, you can store potential energy in the system. In laymans terms, your description was essentially correct.

Back to the subject of big magnets, I worked with a guy who built an electron spectrometer out of two 1 Tesla permanant magnets. It worked by bending the paths of electrons dependant on their velocity. We had to store the thing at least 3 metres from any monitor screens or magnetic storage media. When it came to putting the thing inside a vacuum chamber, he seemed to forget that the chamber was made of steel. It took three men and a big lever about half an hour to get the thing off the chamber wall.

[Brian]

Just a suggestion, you can maybe get better prices on eBay, maybe. I think there's a bunch of people out there with garages full of them, so the price is dropping. I got a 1"X1"X1" cube for $16.00 including postage.

Originally posted by bewareofdogmas




Yeah... http://www.wondermagnet.com/crush.html Ouch!

info on the disc

Composition: NdFeB
Shape: disc
Coating: Nickel Plate
Dimensions: 2" dia X 1" thick
Br max: 12,100 Gauss
Bh Max: 35 MGOe

Wow!

[ceptimus]

There are some really powerful magnets - of the 'injure yourself if you're not very careful' type inside computer hard disk drives.

If you have a broken drive, or an old low capacity one you don't want anymore, take it apart and get the magnets out. The magnets are on either side of the mechanism that moves the read/write head, to the different track positions (the mechanism swings the heads over an arc of maybe 60 degrees.

The magnets are arranged so the magnetism is almost totally confined within the mechanism - so you won't realise how strong they are till you take it apart.

Watch your fingers! These magnets are easily stong enough so that you can put one on the palm of your hand, and another on the back of your hand, and they will hold themselves there, giving your hand a firmish pinch. When they get closer together than the thickness of your hand, they are powerful enough to give you a painful injury.

[Johnny Pneumatic]

Originally posted by richardm
I suppose you've all encountered the Levitron (http://www.levitron.com/) ?

I got one of these for Christmas. It really is amazing :)


Yet another science gadget I have to buy.

[rockoon]

Originally posted by EdipisReks
bewareofdogmas, please remove the pictures and rehost them yourself. stealing other peoples bandwidith is a no-no.

It seems to me.. "rehosting" the image would be theft. Linking to the picture is not. Thats what the internet was designed to do.

[ceptimus]

Originally posted by EdipisReks
bewareofdogmas, please remove the pictures and rehost them yourself. stealing other peoples bandwidith is a no-no. He couldn't do it now, even if he agreed with you. The new anti-editing policy precludes this.