How do I contain a magnet's magnetic field?

In summary, the magnets were shipped in a way that allowed for the magnets to have a strong pull force. The magnets were contained by soft iron shields that had to be removed.
  • #1
Magnetism
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0
I want to buy a Neodymium Iron Boron magnet (N45 or higher), the ones with a very strong pull force. I want to keep it somewhere safe when I'm not doing experiments with it. Is there a way to contain the force so my metals don't fly half way across the room smacking my face along the way? Maybe a box I can put it in? Thanks.
 
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  • #2
OK, they're not exactly that strong. :rolleyes: The strength of a magnet drops off as the cube of the distance. You don't need to block the magnet so much as you just need some distance. If the magnet has several inches separating it from anything coming close (say, by putting it in a medium-sized box) nothing will be unduly attracted to it.

But that being said, the one thing that best "blocks" magnetism is soft iron. The magnetic field will tend to follow the iron rather than passing through it. However, your implementation is a bit usual - usually you're trying to keep magnetism from affecting something inside a box. i.e. the magnetic field will go around the outside of the box rather than thorugh it.
 
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  • #3
Just reading through. Just noticed one thing that bothered me. Magnetism is an inverse square law, so it wouldn't be the "cube" of the distance. moving two meters away would mean 1/4 of the original field strength.
 
  • #4
theantivirus said:
Just reading through. Just noticed one thing that bothered me. Magnetism is an inverse square law, so it wouldn't be the "cube" of the distance. moving two meters away would mean 1/4 of the original field strength.
Can you please supply a citation for this? I think it's the cube but I'm willing to be corrected.
 
  • #5
A monopole field will scale as inverse square. So how will the long range field of two monopoles (= 1 dipole) scale?
 
  • #6
I am sorry. It appears as though I was thinking about the magnetic monopole, wherever that may exist. The magnetic field strength decay has an inverse cube proportionality. Excuse me for the mistake.
 
  • #7
I don't remember the web-site where I purchased 8 large NIB magnets, but I do remember how they shipped them.

When I opened the cardboard box, there were 2 U-shaped/square soft iron "shields' that I had to remove(easily), and the NIB's were inside embedded in some type of styrofoam mold.
I'm sure part of this was due to some postal regulation, but I was impressed.
 

1. How do I physically contain a magnet's magnetic field?

The simplest way to contain a magnet's magnetic field is to surround it with a material that is not easily magnetized, such as a non-magnetic metal or plastic. This will prevent the magnetic field from extending beyond the magnet's physical boundaries.

2. Can I completely block a magnet's magnetic field?

No, it is not possible to completely block a magnet's magnetic field. However, using multiple layers of non-magnetic material can significantly reduce the strength of the magnetic field outside of the containment.

3. How do I create a magnetic shield to contain a magnet's field?

A magnetic shield is typically made of a material with high magnetic permeability, such as iron or nickel. The shield will redirect the magnet's field lines and contain them within the shield's boundaries.

4. What are some common mistakes when trying to contain a magnet's magnetic field?

One common mistake is using materials that are not truly non-magnetic, such as aluminum or stainless steel, which can still be slightly magnetized. Another mistake is not fully enclosing the magnet with the containment material, leaving gaps for the magnetic field to escape.

5. Can the strength of a magnet's magnetic field be controlled within a containment?

Yes, the strength of a magnet's magnetic field can be controlled within a containment by altering the thickness and type of material used. Thicker and more magnetic materials will provide stronger containment, while thinner and less magnetic materials will result in weaker containment.

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