I am Not Clever Enough To...

...think about this (or achieve it); 1) You place a hunk of radioactive metal into a closed space. It might possibly need to be a sealed chamber. 2) Then what you do is you take some magnetic material. 3) You crush it until it become a powder. (Preferrably, the finer the powder, the better it would probably work.) You take the powder and throw it into the chamber. Now, the one thing is that I don't know how this exactly works. You may have to do this in a pretty methodical way to ensure you get consistent results. However... if the experiment works out, then eventually, what you should end up with, is a floating cloud of magnetized particles. It's essentially a magnetic cloud, especially if the granules are of extremely microscopic size. The end result can possible be a sphere, which shows the magnetic field. Please tell me why someone would do this?