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My intuition tells me that this should give more efficient cooling. I basically have nothing to back this up. Thinking about it, it probably makes more sense for dissolving the sugar than cooling the coffee.
The two cup trick is also used in Japan when making green tea, because the fragile tea leaves can be damaged if the water is too hot. I once heard a tea master say that every time you pour the water from one cup to another, it cools down by 10 degrees (celsius). I'm not sure I fully believe him because pouring the water between cups 10 times didn't freeze the water. ;-)
I'll leave it as an exercise, as to what 10 pours will do, but it won't freeze the water; as I don't remember how to solve it and I don't have a piece of paper handy.
And that's not accounting for the specific heat in the state change.
I always stir my coffee in a random way so that you see turbulent movement in the cup as opposed to the whirlpool you get from moving the spoon in smooth circles. My intuition tells me that this should give more efficient cooling. I basically have nothing to back this up. Thinking about it, it probably makes more sense for dissolving the sugar than cooling the coffee.
So I think your intuition is doing pretty well.
on a completely different note, I like my coffee hot :)
Similarly I've often wondered if it results in hotter coffee to mix your milk with the coffee when it goes into the thermos, rather than when it comes out. I'm pretty sure it is better to do it this way - my reasoning is that the hotter black coffee, because of a greater temperature difference with the surroundings, loses heat more rapidly through the thermos walls than the milk + coffee mixture. But I'm unsure how s…
http://maxbrunsfeld.wordpress.com/2011/02/17/on-the-mixing-o...
my result agrees with your intuition.
1) Find person nearby with a drink that has ice in it 2) Use spoon to extract the ice from their glass 3) Put ice in coffee Also, you may need to threaten the person with the spoon to get the ice.
I always stir my coffee in a random way so that you see turbulent movement in the cup as opposed to the whirlpool you get from moving the spoon in smooth circles. My intuition tells me that this should give more efficient cooling. I basically have nothing to back this up. Thinking about it, it probably makes more sense for dissolving the sugar than cooling the coffee.
Your aim is to make sure that every bit of the coffee eventually makes it to the surface (so that the highest-energy molecules there can escape and cause cooling). If you stir regularly then (roughly) each bit of the coffee just moves in a circle, and parts that start out below the surface stay below the surface. If you stir it at random, then (this is probably a theorem, if you define "random" with a bit of care, an…
Does anybody have a supercomputing cluster we could use to run an optimizing search across a whole bunch of fluid flow simulations?
Assume a spherical spoon...
The two cup trick is also used in Japan when making green tea, because the fragile tea leaves can be damaged if the water is too hot. I once heard a tea master say that every time you pour the water from one cup to another, it cools down by 10 degrees (celsius). I'm not sure I fully believe him because pouring the water between cups 10 times didn't freeze the water. ;-)
It won't be a fixed "10 degrees". More like dt = (T_cup - T_room) x cooling factor. I'll leave it as an exercise, as to what 10 pours will do, but it won't freeze the water; as I don't remember how to solve it and I don't have a piece of paper handy. And that's not accounting for the specific heat in the state change.
EDIT I meant to say that entropy is proportional to degrees of freedom, which is logarithmically related to heat energy (except in some weird cases). Anyway, the conclusion was right :-)
Earlier quoted context omitted.
Your aim is to make sure that every bit of the coffee eventually makes it to the surface (so that the highest-energy molecules there can escape and cause cooling). If you stir regularly then (roughly) each bit of the coffee just moves in a circle, and parts that start out below the surface stay below the surface. If you stir it at random, then (this is probably a theorem, if you define "random" with a bit of care, an…
Surely there are some regular motions which could be approximated using a spoon which would more efficiently move the hottest parts of a liquid to the surface than random turbulence? My intuition says sliding the spoon down the side of the mug, then turning the flat side upward and lifting it in the middle of the mug would be one such more efficient motion. Does anybody have a supercomputing cluster we could use to r…