http://www.amasci.com/weird/microexp.html
Are you a kid? Does your microwave oven belong to your parents? If so, then don't even THINK about trying any of these experiments. I'm serious. If I wreck my microwave oven, I can buy another. Also, I'm a professional electrical engineer. I know enough physics and RF effects to take correct safety precautions when I'm experimenting. But you don't know the precautions, so you should be smart: read and enjoy my writing, but don't duplicate my tests unless you grow up to become an electronics tech, engineer, etc., and buy your OWN microwave oven. Disclaimer: This information is presented for your information only. Anyone who tries to duplicate these demonstrations does so entirely at their own risk. There is a chance that you will damage your microwave oven. There is a chance that you will cause a fire. There is a chance that a heated object will explode. Heated water can unexpectedly burst into violent boiling. Messing with a microwave oven is stupid if you don't know what you're doing.