Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: jumbling magnets together

Learn more physics!

Most recent answer: 06/22/2011
Q:
Here is my question what would happen if you threw a bunch of magnets of various sizes/masses together? I would think they would jumble around trying to attract or repel eachother. I would also assume they might form clumps that would connect together until eventually they would form one huge mass or several clumps of different sizes pushed away from eachother. Now I come to wonder What would happen if you had an infinite number of magnets that were infinitely "small" so there was never "empty space" These magnets would at least I would think gain speed and momentum or lose it depending on the size,mass,momentum and speed of the others around them smashing into eachother causeing them to bounce and break off in different directions. but the clumps themselves would be made of smaller moving clumps infinitely, so empty space would just be an illusion relative to size(like how we cant see air)and no matter how "far" . It seems there would be an infinite rate at wich things could move. Which might explain how things can be extremely similer but never exactly the same. It seems like then there would only be 2 forces attraction and repultion just at different rates relative to size,mass etc. But if everything was infinitely small then wouldnt those just be due to "movement" of smaller and smaller "stuff". I know theres holes in my line of thought, but I personally don't think anyone could ever really fathom whatever is really out there Just random thought I guess
- JASON (age 24)
NASHVILLE, TN, US
A:
If you packed a lot of similar magnets together, they'd form regular magnetic patterns. They line up oriented the same way end-to-end, but opposite ways side-to-side. If they're all cylinders, I suppose the pattern would be square in the sideways plane, since that allows each sideways neighbor to be oppositely oriented.  The net pattern would have no average magnetic moment. If you were to squeeze them, forcing them into a hexagonal pattern, I'm not sure what would happen, since that pattern won't allow each neighbor to be oppositely oriented.

Now what would happen if they're all different sizes and shapes? I don't know, but there's a suggestive relevant fact. If you take a bunch of identical non-magnetic spherical beads and slowly shake them around to let them settle down, they form a regular crystalline pattern. If you do the same with beads with more of a range of sizes, they also pack together rigidly, but in a random-looking pattern, like a glass. It's possible that a sufficiently heterogeneous collection of little magnets would form some sort of dipole glass.

I couldn't quite follow the more complicated part of your question. For searching purposes, you should know that certain types of random frozen magnets are called "spinglasses". There are other types of interesting frozen magnet systems which you might find by looking for "frustrated magnets". (Those hexagonally packed magnets would be frustrated, since there's no way to line them all up properly with each neighbor.

Mike W.

(published on 06/22/2011)

Follow-up on this answer.