I was getting my fix of knowledge today and stumbled across a great optics experiment done Emeril-style. From the days of childhood I imagined great things to do with microwaves: cook insects, check the heating capability of the microwave using an electronic thermometer, make sparkles with old AOL CDs. Never in a million years did I think of measuring the speed of sound with it… IDIOT! I could have been famous!
Measure The Speed of Light With Chocolate and a Microwave
The only equipment you need for this experiment is a microwave, a ruler and chocolate, cheese or any other food that melts. Remove the turntable from the microwave and replace with chocolate on a plate (so the plate does not rotate), and heat until it just starts to melt – about 20 seconds, depending on the power of the oven. There will be some melted hot spots and some cold solid spots in the chocolate. The distance between the hot spots is half the wavelength of the microwaves, and the frequency of the microwaves will often be printed on the back of the oven. The speed of light is equal to the wavelength multiplied by the frequency of an electromagnetic wave (microwaves and visible light are both examples of electromagnetic waves).
So from this simple experiment, and some easy math, you can work out the speed of light from Milky Way Magic Stars®!