And now, after heating it in a flame... it's no longer magnetic.

What just happened?

Well, to build a magnet, all you need to do is find a bunch of magnetic atoms (that's

easy - they're the ones with half-filled electron shells in the middle of any of the major blocks

of the periodic table) and then make a compound where the magnetic fields of the atoms align

in the same direction - this is Ferromagnetism, named after Iron, which is pretty darn magnetic.

However, it's not so easy - sometimes the atoms actually want to align their magnetic

fields in alternating directions - this is called "anti-ferromagnetism," and it means

the bulk material won't have a magnetic field at all.

Or, sometimes the tendency of the atomic magnets to align (or anti-align) is just too weak

to overcome their intrinsic jiggling - that is, their temperature!

In which case, even though all the individual atoms in the material are magnetic, once more

the material as a whole isn't.

However, in a strong external magnetic field, the atoms do tend to align with each other

in the direction parallel to the field.

This is called "para-magnetism," and liquid oxygen is a great example - it's attracted

by a magnet, though it doesn't stay magnetized afterwards.

But let's get back to the question - how do you destroy a magnet?

Well, a material can only be ferromagnetic if its temperature is low enough: above a

certain point, the nicely ordered atomic magnetic fields "melt" into disorder, just as ice crystals

melt into water when heated past zero celsius.

So to destroy a magnet, you just need to heat it up past its "magnetic melting point", called

the "Curie Temperature" - it probably won't look like much is happening, but once the

atoms are jiggling around enough, when they cool off, their magnetic fields will no longer

all point in the same direction.

Magnet destroyed!

And just as different elements melt from solid to liquid at different temperatures, they

also melt from being ferromagnetic to paramagnetic at different temperatures, which you can explore

in this sweet interactive periodic table.

Which also plays all

of

the Periodic Table

of Videos.