Determining the speed of light, using marshmallows

[daveboling]

Found as a link within one of the APOD posts:
http://www.physics.umd.edu/icpe/newslet ... rshmal.htm

dave boling

[Tor]

Beautifully simple..

[Tunborough]

Very clever method. However, it may work only with microwaves from which you've removed a turntable. Those without a turntable to begin with will have some other mechanism inside to distribute the radiation uniformly. (Makes me think of Leslie speakers.)

[Nanohedron]

It amazes me how people figure this stuff out.

[an seanduine]

Elegant use of the standing wave in a tuned chamber.

Bob

[chas]

My experience is that microwaves tend to have one or two hot spots. I base this on the dessicants that turn color when they dry out, so much less sensitive than the melting of marshmallows. I'll have to try this. I have no doubt that it works, since this was submitted to American Journal of Physics (an educational journal).

One question jumps out at me -- this requires a standing wave; anyone know why there would be a standing wave in the oven?

[walrii]

anyone know why there would be a standing wave in the oven?

Because there is no place to sit? Sorry, Chas, the Devil made me say it!

[an seanduine]

I like walrii's answer better than mine
Back in the dark ages when I sold the silly things, I was told by a technician that the cooking chamber was a 'tuned' space to increase the efficiency of energy transfer from the magnetron to food in the cooking chamber. The cooking frequency was supposed to be close to the resonant frequency of the water molecules in the food. This was an Amana tech back in Iowa. My experience was that this might have been true for Amana branded ovens, but other cheaper, less well engineered brands, maybe not so much.

The story ran: A GE tech was tuning some radar gear tuned to 970 (980??) mhtz. He had a candy bar in is shirt pocket in preparation
for his break. When he leaned over the unshielded, powered up rig the bar promptly melted. Voila! Microwave Cooking. This frequency transferred maximum energy to fats. Later they changed to 2450 mhtz.

Bob