007 ... they will be out to collect your "shoe" since you have forgotten ... :good:
Microwave excites the moisture molecules present in just about everything. The excited molecules run faster, and faster, and start to collide with other molecules thus causing friction withing the material.
Heat is the by product of all this energy and motion. This heat is also why popcorn goes pop in the microwave. It's just steams way of getting free.
If you want to experiment with microwaves, just heat up a cup or so of water in a reasonably sized container, put some salt in a spoon - not much though -heat the water to a boil and remove from the microwave. Holding your hand WAY up above the heated water, slowly pour the salt into the water. Be prepared for a violent reaction
immediately
as the salt is 'cracked' and the water explodes from the rapid release of energy.
If you want to ruin a perfectly good microwave and create a violent electrical storm in the oven, just put a small crumpled up piece of aluminum foil in the microwave, close the door, and turn on the timer. It won't take but a moment to flash and burn out the electronics of the microwave ... and the chance of a fire is really great too. Also, not removing ALL the foil from the top of a peanut butter jar does the same thing ... please DAMHIKT!
You do these "experiments" at your own risk and peril. I ain't gonna be there to stop you, so I ain't gonna be responsible for anything that happens either. Don't write, call, or e-mail. I just don't want to say I told you so!