Leftover Valentine’s Chocolate? Use It to Measure the Speed of Light

[n2doc]

By Kathy Ceceri
February 15, 2010 |
8:00 am |
Categories: Projects and Activities, Science and Education

If you’re a long-time reader, you may remember the great leftover Easter Peeps microwave experiment. Well, today we’re going to be nuking leftover Valentine’s Day chocolate to demonstrate one of the constants of physics, the speed of light. Chocolate makes a very appropriate medium, because the heating property of microwaves was first discovered by a scientist whose candy bar melted in his pocket when he got too close to a microwave device being tested for use in radar.

WARNING: This experiment may take several tries to get right. We are not responsible for any weight gained. To avoid familial strife, be sure to only do this experiment with your own chocolates or with candy which you have been authorized to access. You can probably find some leftover boxes on sale this week.

The demonstration works because microwave ovens produce standing waves — waves that move “up” and “down” in place, instead of rolling forward like waves in the ocean. Microwave radiation falls into the radio section of the electromagnetic spectrum. Most ovens produce waves with a frequency of 2,450 megahertz (millions of cycles per second). The oven is designed to be just the right size to cause the microwaves to reflect off the walls so that the peaks and valleys line up perfectly, creating “hot spots” (actually, lines of heat).

What you do with the candy is to find the hot spots and measure the distance between them. From that information, you can determine the wavelength. And when you multiply the wavelength by the frequency, you get the speed! Here’s what you do:

more:

Read More http://www.wired.com/geekdad/2010/02/leftover-valentines-chocolate-use-it-to-measure-the-speed-of-light/

[Captain Hilts]

1. Neat!

[frazzled]

2. Not with my Neuhaus chocolates!

But thanks for the experiment--it was very educational.

[ashling]

3. But don't we already know the speed of light?

Not me personally, but people like, for instance, Bill Nye the Science Dude, and people like that. So wouldn't that be kinda' like an unnecessary waste of chocolate and stuff?

[Fumesucker]

4. Replication of results is the essence of science..

It's not enough to perform an experiment once, it must be performed many times by many investigators and the results compared.

:)