3 ms·

Some napkin math: It looks like mouse/rat weight varies widely, I'm going to be lazy and just pick 400g and from what I can tell, that also means about 400cm^2

by mbell 8y ago

Some napkin math: It looks like mouse/rat weight varies widely, I'm going to be lazy and just pick 400g and from what I can tell, that also means about 400cm^2 body volume. Ultimately all that matters is the density though, which is unsurprisingly pretty close to water, close enough I'm not going to bother with it. microwave power density = 1200W * 0.75 (efficiency estimate) / 22500cm^3 (interior volume) = 0.04W/cm^3 So in this experiment we have 1.5w to 10w * 0.4kg = 0.6W to 4W In a 1200W microwave: 400cm^2 * 0.04W = 16W In an 600W microwave: 8W (tho a 600W microwave is probably smaller so this may be low) So a microwave would be 2-4 times more radiation than what they were exposed to in this experiment. Likely my power-to-rat-delivery estimate is a bit low for the microwave since I didn't take into account any sort of chamber resonance / reflection in the microwave enclosure, just it's baseline power density. Though, it would still get no where near dumping all it's power into something the size of a rat.

blattimwind 8y ago
You're assuming that the interior of the microwave behaves like an uniform field, so if you occupy 50 % of the volume, only 50 % of the power can be coupled to that object. This is not the case. There are some (big) losses in how power is coupled to the object in the microwave, but it's not 98 %. Also note that the power is coupled through the surface, so for power transfer it's mostly important that you have (1) big surface (2) surface depth exceeding penetration depth. The exact coupling is "dirty" (near field), so it doesn't just depend on surface area, but also surface structure, precise alignment etc. E.g. a ball of mashed potatoes takes longer to heat up than a ring/donut-shaped arrangement of the same mashed potatoes.
hu3 8y ago
So your math is telling me that a mice (10w/kg in the experiment) would survive 25 days in a 600w microwave oven at full power? Because they survived in the experiment. My 600w microwave oven cooks eggs in 2 minutes. Pretty sure a mice wouldn't last an hour inside it even at 1/4 power.

by mbell 8y ago

blattimwind 8y ago

You're assuming that the interior of the microwave behaves like an uniform field, so if you occupy 50 % of the volume, only 50 % of the power can be coupled to that object. This is not the case. There are some (big) losses in how power is coupled to the object in the microwave, but it's not 98 %. Also note that the power is coupled through the surface, so for power transfer it's mostly important that you have (1) big surface (2) surface depth exceeding penetration depth. The exact coupling is "dirty" (near field), so it doesn't just depend on surface area, but also surface structure, precise alignment etc. E.g. a ball of mashed potatoes takes longer to heat up than a ring/donut-shaped arrangement of the same mashed potatoes.

hu3 8y ago

So your math is telling me that a mice (10w/kg in the experiment) would survive 25 days in a 600w microwave oven at full power? Because they survived in the experiment. My 600w microwave oven cooks eggs in 2 minutes. Pretty sure a mice wouldn't last an hour inside it even at 1/4 power.