Measure The Speed Of Light With Your Microwave

maddmike writes "There is a very interesting article on About.com that shows how to measure the speed of light using your microwave to melt chocolate. "

Comments

Measure the frequency of your microwave instead

[boa13]

Summary of the method used in the article:

* Slightly melt chocolate chips in your microwave
* Measure distance between melted spots
* This gives you (half) the wavelength of your oven
* Multiply by the frequency of your oven, you get the speed of light

That's certainly interesting, but guess what? Many scientists have done better (and much more expensive) measures, so we already know the speed of light quite well.

What we might not know as well is the frequency of your oven. So I suggest you reverse the above formula, and you measure the frequency of your oven (not always printed on the back, as the article admits) this way.

Re:Funny this should come up

[MillionthMonkey]

I did the rapidly rotating octagonal mirror experiment in college. I got 2x10^8 m/s which is pretty slow. Either the mirror speed was off, or between runs I might have jostled the paper on the wall with the pencil marks marking the beam position.

You can measure the wavelength of light pretty easily with a ruler. But it has to be one of those shiny metal rulers, and it has to have black millimeter marks. Shine your laser onto the black marks at a shallow angle, measure the positions of the diffraction spikes that are reflected onto the wall, and from that, calculating the wavelength is trivial. It works pretty well.

Re:Funny this should come up - or maybe not

[frovingslosh]

You didn't measure the speed of light, you measure a wavelength. Unless you can show that you had some way to confirm the frequency of the light source that is not dependent on knowing the speed of light, then when you looked up the frequency of the light source you were effectively looking up the speed of light and using it to determine the speed of light. No wonder your answer came out close!