Measuring the Speed of Light With Valentine's Day Chocolate

Cytotoxic writes "What to do with all of those leftover Valentine's Day chocolates? — a common problem for the Slashdot crowd. The folks over at Wired magazine have an answer for you in a nice article showing how to measure the speed of light with a microwave and some chocolate. A simple yet surprisingly accurate method that can be used to introduce the scientific method to children and others in need of a scientific education."

Comments

Re:Slashdot doesn't recongnize this holiday!

[Bakkster]

Aslo, the article is wrong:

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.

Ocean waves don't "move forward".

While the individual particles do not, the wave itself does.

He is mistaken on the meaning of a standing wave. It is not the same as a transverse wave (which seems to be why he is comparing them to a longitudinal wave).

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).

Disproved by direct observation. Go into any store and you'll see microwaves in various sizes. The perfect microwave doesn't have "hot spots".

Again, he's wrong about it being 'designed' for the purpose of having hot spots, but the design does result in hot spots. These occur regardless of oven size, they will simply be located in different locations. This is caused by reflections off internal surfaces acting like two signal sources.

While it may be conceivable to create a 'perfect' microwave with no standing wave nodes, it would be pointless. Besides, he wasn't using an 'ideal' microwave, just a regular off-the-shelf microwave, which does have standing waves.