YAPQ: Non-homework physics question

Chaotic42

Lifer
Jun 15, 2001
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Imagine a styrofoam bowl of 722mL capacity that has its bottom removed has been placed upside down in a microwave.

Further imagine that a hamburger with a mass of 500 grams has been placed on top of the inverted bowl.

Also imagine that the entire bowl/hamburger system started at STP and was then microwaved on high for two minutes.

At the sounding of the alarm, is the temperature inside the bowl less than, equal to, or greater than the temperature outside of the bowl?
 

Atheus

Diamond Member
Jun 7, 2005
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not a physicist, but i reckon temp depends on distance from focal center of the radiation, and how close to the frequency of the waves the resonant frequancy of the material is.
 

Atheus

Diamond Member
Jun 7, 2005
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Originally posted by: iwantanewcomputer
less, the water in the burger goes to vapor and greatly increases pressure which increases T

Good point. The bowl would also insulate the small area inside it. Wouldn't most sten escape upward though?
 

Midlander

Platinum Member
Dec 21, 2002
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Real answer: Microwaves heat fat faster than air. The hamburger gets hot and heats the air around it. The bowl (not really Styrofoam, but that's another topic) insulates the air under the bowl from the heat of the hamburger. Therefore, the air outside the bowl is hotter.
 

TuxDave

Lifer
Oct 8, 2002
10,571
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Originally posted by: Midlander
Real answer: Microwaves heat fat faster than air. The hamburger gets hot and heats the air around it. The bowl (not really Styrofoam, but that's another topic) insulates the air under the bowl from the heat of the hamburger. Therefore, the air outside the bowl is hotter.

I thought that the bowl had the bottom removed so half the hamburger is exposed to a small insulated area and the other half is exposed to the rest of the microwave.
 

Midlander

Platinum Member
Dec 21, 2002
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Originally posted by: TuxDave
Originally posted by: Midlander
Real answer: Microwaves heat fat faster than air. The hamburger gets hot and heats the air around it. The bowl (not really Styrofoam, but that's another topic) insulates the air under the bowl from the heat of the hamburger. Therefore, the air outside the bowl is hotter.

I thought that the bowl had the bottom removed so half the hamburger is exposed to a small insulated area and the other half is exposed to the rest of the microwave.

Uh oh, I missed that. :eek: Then I change my answer. The volume of air under the hamburger is smaller than that around it, so it will heat faster.
 

iwantanewcomputer

Diamond Member
Apr 4, 2004
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Originally posted by: Midlander
Real answer: Microwaves heat fat faster than air. The hamburger gets hot and heats the air around it. The bowl (not really Styrofoam, but that's another topic) insulates the air under the bowl from the heat of the hamburger. Therefore, the air outside the bowl is hotter.

this is also true. the microwaves have a very small heating effect on the air, they only heat the water/polar molecules in meat. the only way

Tinside the bowl is greater is if the microwave is really big, so the average air temp is still lower. this would also need the heat transfer through the bowl to be relatively high

edit: I also missed the bottom part. I change my answer