Timeline for Will a tall narrow cup keep a cup coffee warmer than a more evenly dimensioned cup?
Current License: CC BY-SA 3.0
8 events
| when toggle format | what | by | license | comment | |
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| Jul 8, 2014 at 19:13 | comment | added | C. Towne Springer | I have seen your chemtrails! | |
| Jul 8, 2014 at 7:03 | comment | added | 299792458 | Except for the fact that we use saucers instead of cars, here on Mars :P | |
| Jul 8, 2014 at 7:02 | comment | added | 299792458 | Right, my answer applies to the coffee I'm sipping here on Mars! I never disagreed about the issue of optimality and completely buy the intermediate sweet spot. But the point I'm trying to make is that convection effects won't make a huge difference on this scale (size of a typical cup, that we have here on Mars :P), that's why we can neglect convection. They do in the case of water boiling in a pan, because there is significantly higher temperature difference involved. In a nutshell, all I'm advocating is - let's not use General Relativity to describe the motion of a car moving on a road. :) | |
| Jul 8, 2014 at 6:53 | comment | added | C. Towne Springer | If I recall right, convection has a term proportional to the two thirds power of g so the answer can change from planet to planet. Anyway, take an extreme - a tall ceramic straw. Certainly something shorter will cool slower and something taller than a saucer will cool slower. There is a sweet spot in between. No? | |
| Jul 8, 2014 at 6:41 | comment | added | 299792458 | I don't disagree with the ''optimal'' issue, but the question is how big a difference would these convection effects make to this problem. I would be very surprised if inclusion of convection effects reverses this conclusion, since we know about this experimentally - by drinking coffee everyday! Anyways, please go ahead with the full calculation :) | |
| Jul 8, 2014 at 6:37 | comment | added | C. Towne Springer | The taller one will have stronger convection currents which will stir the coffee and more vigorously expose the hottest liquid to air where it cool faster by evaporation. But the surface area is less. The air on the outside will also convect and at a higher velocity for the tall cup. I suspect there is an optimal size for a cylinder and fixed volume and the calculation is far from simple. | |
| Jul 8, 2014 at 6:02 | history | edited | 299792458 | CC BY-SA 3.0 |
added 344 characters in body
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| Jul 8, 2014 at 5:56 | history | answered | 299792458 | CC BY-SA 3.0 |