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Originally posted by ivangrice
I was kind of hoping that there'd be some mathematical analysis...
yeah there could be but then you would have to factor in the the fact that a thermos is insulated and i dont know how you could do that

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Originally posted by ivangrice
You do if you can explain it in scientific terms..
http://hypertextbook.com/physics/thermal/radiation/

It says the flask would reduce the heat loss by a factor of 13.

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Originally posted by thenegativeinfinity1
really you couldnt do this with out opening the can and thet is a factor is there such a thing as a wireless digital thermometer
You could use a digital set up but wouldn't the wires conduct a certain amount of heat away from the body of water, thus rendering the experiment null???

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Originally posted by ivangrice
Thermos Jupiter 38 (1 litre). One standard twist and pour stopper. Water at exactly 100 degrees C when sealed in an environment at sea level with ambient temperature 20 degrees C.

How long?

:-)
HEY! You're trying to get us to do your physics assignment for you! 🙂

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It would theoretically take eternity to reach thermal equilibrium because its approach will be asymptotic towards 20 dec C (getting closer and closer to it without reaching it). Not taking into account other influences.

I could have a go at making an approximation to the amount of time to get below a certain temperature (e.g. 20.1 deg C). That would be making assumptions about thermal conductivity of the materials, amount of vacuum gap between the inner and outer casing and how good the vacuum is (to reduce convection). Will just assume a perfect vacuum for simplicity. It is late here now though and off to bed. Will try tomorrow. 🙂

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Originally posted by lausey

It would theoretically take eternity to reach thermal equilibrium because its approach will be asymptotic towards 20 dec C (getting closer and closer to it without reaching it). Not taking into account other influences.

Now all the engineers, college students and people who read anything about physics KNOW that's wrong! The liquid will reach room temperature within 36 hours dude. Trust me, I am a facility designer and have to work the math for air conditioning offices. However, I cannot answer the question because too many principles are missing in the formula.


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Originally posted by Grandmaster bater
[b]Is the thermos in a vacuum and travelling at near the speed of light?
Not exactly. The thermos was in a vacuum and traveling at the speed of dark.

For my figures to be valid, the vacuum has to be turned on which, unless it's a very quiet vacuum, will scare the dog.

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Originally posted by ivangrice
How long would it take for a tightly-sealed thermos flask of boiling water to cool to room temperature?

How sad is that?
22hrs 36 min 12 sec.

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Originally posted by arrakis
Now all the engineers, college students and people who read anything about physics KNOW that's wrong! The liquid will reach room temperature within 36 hours dude. Trust me, I am a facility designer and have to work the math for air conditioning offices. However, I cannot answer the question because too many principles are missing in the formula.



Well, you would have to enlighten me, because I do actually have a BSc in Applied Physics.

I will look into it more because my understanding of it was that in a closed thermodynamic system it would follow a curve that approaches thermal equilibrium ad infinitum.

I will have to go back and look through my lecture notes. 🙂

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Originally posted by ivangrice
How long would it take for a tightly-sealed thermos flask of boiling water to cool to room temperature?

How sad is that?
Would it be ok, in the interests of science, if we inserted a cat into the boiling water as a kind of litmus test to see if it is really hot? I broke the thermometer.

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Originally posted by hopscotch
Would it be ok, in the interests of science, if we inserted a cat into the boiling water as a kind of litmus test to see if it is really hot? I broke the thermometer.
I recoment a cute fluffy rabbit instead.. they scream like a MF when there in pain.. so i think it would be a better indicator.