You know how microwave ovens heat or defrost your food unevenly? You must either rotate or stir your food between zaps to get it "done." Lenore at Evil Mad Scientist Laboratories accidentally uncovered the pattern her microwave uses when she heated some Indian snack crackers called appalams.
And then, like any good scientist, she recreated the entire experiment in four other microwave ovens to see if the results could be duplicated. Link
Holy crap!
As an area of the cracker cooks, it bubbles up in just a few seconds, leaving clear marks as to where there is microwave power and where there isn't. For this particular microwave, Saturn-shaped objects will cook evenly.
Obviously what is happening is that there are two hotspots in this microwave: one in the center, and one offset from center which traces out a circle thanks to the rotating plate in the bottom.
And then, like any good scientist, she recreated the entire experiment in four other microwave ovens to see if the results could be duplicated. Link
1. demonstrating the standing waves in a microwave oven using chocolate
http://thehappyscientist.com/science-video/microwave-chocolate
2. Continuing with the experiment to show how you can use the melted/burned chocolate to determine the speed of light.
http://thehappyscientist.com/science-video/light-speed-chocolate