Answer to Question #2 in Electromagnetism for Dave
Why the heated magnet loses its magnetic properties?
Magnetic materials have a specific structure, consisting of the so-called domains - tiny magnets inside the material. If the domains are oriented along one direction, then they produce a significant cumulative effect, and the material is called a magnet. Heating leads to the loss of the selected domains' orientation and, correspondingly, of the magnetic properties of the material.