What's cooler? The coffee at the bottom of the cup or the coffee at the top of the cup?

[KingofCamelot]

Originally posted by: arcenite
When coffee steams, it steams from the top... not the bottom.

The only way for steam to escape a cup, would be through the top. So, how do you know the steam isn't coming from the bottom, and working its way up and through the top?

 

[Circlenaut]

bottom because the cooler liquid sinks. Water becomes more and more dense until 4*C (most dense) below that it's less dense. The VERY top might be the coolest because of evaporation ( like the first mm) That's my 2 cents.

 

[spidey07]

Originally posted by: dullard
Standard mug, 2/3rds full with boiling water, measured about 5 mm from top and 5 mm from bottom as close to the center of the mug as I can get.

Time: Top Temperature in °C, Bottom Temperature in °C
10 sec: 95, 94
1 min: 89, 89
2 min: 86, 86
3 min: 82, 82

convection for the win!!!!

Thanks a bunch for the experimental data.

 

[Otaking]

 

[dullard]

Originally posted by: spidey07
convection for the win!!!!

Thanks a bunch for the experimental data.

No significant temperature difference after 10 minutes. Now, where do I vote?

 

[spidey07]

Originally posted by: dullard

Originally posted by: spidey07
convection for the win!!!!

Thanks a bunch for the experimental data.

No significant temperature difference after 10 minutes. Now, where do I vote?

can't wait till he has to explain this...

"honey we're both wrong"

her - "no, I'm right"
"honey we've measured it"
her - "doesn't matter, I'm right"
"but thermodynamics don't just get broken"
her - "doesn't matter, I'm right"

 

[BurnItDwn]

The answer is NEGLIGABLE.

Also, 42 is a correct answer.

 

[WobbleWobble]

Originally posted by: dullard

Originally posted by: spidey07
convection for the win!!!!

Thanks a bunch for the experimental data.

No significant temperature difference after 10 minutes. Now, where do I vote?

Thanks Dullard

I've added a new voting option.

 

[spidey07]

Originally posted by: WobbleWobble

Originally posted by: dullard

Originally posted by: spidey07
convection for the win!!!!

Thanks a bunch for the experimental data.

No significant temperature difference after 10 minutes. Now, where do I vote?

Thanks Dullard

I've added a new voting option.

good, cause I wasn't voting without one.

 

[WobbleWobble]

Originally posted by: dullard
Standard mug, 2/3rds full with boiling water, measured about 5 mm from top and 5 mm from bottom as close to the center of the mug as I can get.

I'm rounding off decimal points, since my type E thermocouple is only accurate to +- 0.5°C.

Yes, my measurements do cause some disturbance, but this is just a fun quick exercise.

Time: Top Temperature in °C, Bottom Temperature in °C
~10 sec: 95, 94
1 min: 89, 89
2 min: 86, 86
3 min: 82, 82
4 min: 79, 79
5 min: 76, 76
6 min: 74, 74 (close to being off by a degree, but rounding minimizes differences)
7 min: 72, 71 (a clear 1°C colder at the bottom)
8 min: 70, 69
9 min: 67, 67
10 min: 66, 65

Looks like the difference is negligible. Experiment ending at 10 min mark.

But the bottom is 1C cooler right?

Now I realize that the difference is minimal. Thanks for settling this Dullard.

We were having a fairly amusing argument, like I would be like you can skim the top of a hot liquid (soup), but how the hell do you skim the bottom with your spoon?