Chatroom
 

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Bad Astronomy and Universe Today Forum > The Proving Grounds > Against the Mainstream
Register FAQ Members List Calendar Mark Forums Read

   

Closed Thread
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 14-April-2004, 02:15 AM
darkdev's Avatar
darkdev darkdev is offline
Established Member
 
Join Date: Apr 2004
Location: Madison, Wisconsin
Posts: 272
Default "static" rotational/pole-less magentic field

Is it possible to create a magnet, in a circular shape, such that there is no clear north or south pole?

For instance, if you take a bar magnet, and cut it in half, in the middle, you get two magnets both with N/S poles:
[N---S] becomes [N-S] [N-S]

If you bend this magnet into a circle first, and attach the N and S poles, and the cut it elsewhere and straighten it out, you end up with another bar magnet with definate N/S poles.

So... if you can create a poleless or continuous magnet (in the shape of a doughnut), would a compass needle centered over the magnet spin forever looking for a pole? Can we use this rotation as a fuel-less electromagnetic power supply?

hmmm.... doughnuts.....
  #2 (permalink)  
Old 14-April-2004, 02:25 AM
milli360's Avatar
milli360 milli360 is offline
Established Member
 
Join Date: Dec 2003
Location: NC, USA
Posts: 2,464
Default Re: "static" rotational/pole-less magentic field

Quote:
Originally Posted by darkdev
So... if you can create a poleless or continuous magnet (in the shape of a doughnut), would a compass needle centered over the magnet spin forever looking for a pole?
It doesn't look for a pole, it aligns itself with the field. With no N-S direction, there's no field. No spinning.
Quote:
Can we use this rotation as a fuel-less electromagnetic power supply?

hmmm.... doughnuts.....
There's a reason they call it dough nut
  #3 (permalink)  
Old 14-April-2004, 02:49 AM
Patrator Patrator is offline
Established Member
 
Join Date: Mar 2004
Location: Leicester, UK
Posts: 111
Default

darkdev wrote:
Quote:
Originally Posted by darkdev
So... if you can create a poleless or continuous magnet (in the shape of a doughnut), would a compass needle centered over the magnet spin forever looking for a pole?
It's quite a while since I did any work on magnets but IIRC.

If you create a poleless magnet in the shape of a doughnut (incidentally it's called a Toroid), the magnetic flux follows a circular path mostly within the toroid. It's the path of least magnetic resistance i.e. highest permeability. As Milli360 has mentioned, the compass needle will simply align itself with the lines of flux or field if you prefer. If you placed a compass exactly in the centre of the toroid, where there is no net flux, the compass would point North (because the Earth's magnetic field is still present!). Anywhere over the toroid and it will point at a tangent to the edge of the toroid.
__________________
Ignorance is the night of the mind, but a night without moon and star. - Confucius
  #4 (permalink)  
Old 14-April-2004, 03:01 AM
darkdev's Avatar
darkdev darkdev is offline
Established Member
 
Join Date: Apr 2004
Location: Madison, Wisconsin
Posts: 272
Default nuts

I actually swapped toroid for doughnut just to make the Simpsons reference.

Thanks for the answers. That makes a lot of sense.

Since I'm new, is there a forum already open discussing the true source of magnetism? The search engine here seems to suggest that magnets come up but are not a topic... maybe I missed it?

Quote:
Originally Posted by milli360
There's a reason they call it dough nut
"Nuts" is having a question and not seeking the answer, or assuming your instinctual response is correct.
  #5 (permalink)  
Old 14-April-2004, 03:54 AM
Ricimer Ricimer is offline
Established Member
 
Join Date: Apr 2004
Location: California
Posts: 588
Default

actually, a toroid, like a solenoid, has an isolated magnetic field. THe magnetic field does not extend outside of the coiled wire. So placing a magnet, even over the ring, shouldn't cause a deflection.
  #6 (permalink)  
Old 14-April-2004, 12:07 PM
TriangleMan's Avatar
TriangleMan TriangleMan is offline
Order of Kilopi
 
Join Date: Dec 2002
Location: Qatar
Posts: 3,528
Default Re: nuts

Quote:
Originally Posted by darkdev
Since I'm new, is there a forum already open discussing the true source of magnetism? The search engine here seems to suggest that magnets come up but are not a topic... maybe I missed it?
Nope I don't recall any other recent threads on magnetism so this would be the right place for it.
  #7 (permalink)  
Old 14-April-2004, 12:10 PM
darkdev's Avatar
darkdev darkdev is offline
Established Member
 
Join Date: Apr 2004
Location: Madison, Wisconsin
Posts: 272
Default

What is the "source" of magnetism?
  #8 (permalink)  
Old 14-April-2004, 12:18 PM
PhantomWolf's Avatar
PhantomWolf PhantomWolf is offline
Order of Kilopi
 
Join Date: Mar 2004
Location: Lost Deimos Moon Base
Posts: 5,663
Send a message via ICQ to PhantomWolf Send a message via AIM to PhantomWolf Send a message via MSN to PhantomWolf Send a message via Yahoo to PhantomWolf
Default

It's caused by electron spin, though the details are quite intricate nd I can't be bothered looking them up.
__________________
Howling from the Shadows

It must be fun to lead a life completely unburdened by reality. --- JayUtah

You can't reason an irrational person out of an irrational belief. --- Noclevername

Apollo: The History and the Hoax
Enter the World of Athran
  #9 (permalink)  
Old 14-April-2004, 12:28 PM
darkdev's Avatar
darkdev darkdev is offline
Established Member
 
Join Date: Apr 2004
Location: Madison, Wisconsin
Posts: 272
Default

That much I knew, I am wondering what the mechanism is I guess, like gravity is local spacial configuration (spacetime curvature), does magnetism as a distortion in spacetime? Can we express E,M,G as a 3d waveform? It seems to be for EM.
  #10 (permalink)  
Old 14-April-2004, 12:53 PM
Patrator Patrator is offline
Established Member
 
Join Date: Mar 2004
Location: Leicester, UK
Posts: 111
Default

Quote:
Originally Posted by ricimer
actually, a toroid, like a solenoid, has an isolated magnetic field. THe magnetic field does not extend outside of the coiled wire. So placing a magnet, even over the ring, shouldn't cause a deflection.
Whilst this statement is quite correct, it applies to an induced magnetic field via an electric current. I believe Darkdev was talking about a permanent magnet with field alignment in a circular direction around the toroid. In this case, the magnet, whilst giving the overall effect of no poles, consists of many N-S domains all aligned around the circumference. The bulk of the field will remain within the toroid, but will, to a degree, extend outside.
__________________
Ignorance is the night of the mind, but a night without moon and star. - Confucius
Closed Thread


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT. The time now is 10:00 AM.


Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2009, Jelsoft Enterprises Ltd.
LinkBacks Enabled by vBSEO 3.0.0
©  2006 Bad Astronomy and Universe Today