brooksmoses | This is not an update; it is a random thought.

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Fact 1: Microwave ovens work because they produce microwaves tuned to a vibratory frequency of liquid water.

Fact 2: Microwave ovens are rather poor at defrosting chicken; the parts that get defrosted first become partly cooked by the time the remainder of the chicken is defrosted.

Question Arising From These Facts: Would it be possible to build a microwave oven that was tuned to a vibratory frequency of solid water that would defrost chicken properly?

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From:

brooksmoses

Hmm -- I had forgotten that I needed to be a bit more clear on that. After hanging around spectroscopists for most of my grad school career, I tend to use "vibratory frequencies of the material" in this sort of context as shorthand for "vibratory frequencies of the molecules in the material".

And (see the link I posted in another comment) the molecular-scale absorbtion can indeed tell the difference between liquid and solid phases; when the molecules are in a solid, the intermolecular forces contribute to holding the atoms in relative position, and so the resonance frequencies are a bit higher. The interactions with microwaves are a bit more complicated than simple vibratory resonance, but it turns out (see the second link) that ice is practically transparent to the microwaves in microwave ovens even though liquid water absorbs them fairly well.

Interestingly, you can even tell the temperature of a gas by looking at its absorbtion spectrum. But that one's much simpler physics -- for an immobile molecule, you get sharp absorbtion peaks. As the temperature of the gas increases, the molecules move faster and faster, and so you get doppler effects that broaden the peaks, and by measuring the width of the peaks, you can tell the temperature.

From:

seawasp

Okay, you kicked my metaphorical ass around on that. At least you didn't begin it with "Ryk, you ignorant slut." ;)

If that is the case, then it should be possible to design one that shifts its frequency, if frequencies can be controlled accurately enough, to affect frozen water preferentially.

Of course, I just use my own microwave defrosting approach which avoids cooking the bird in places, but that approach requires that you experiment to know the characteristics of your particular oven.