yes, a machine that produces Ice cream so cold that it takes months to melt. I wonder, how long it would it take a 4L tub of ice cream at absolute zero to melt in 20 degrees celcius. I guess you would need the coefficient of the ice cream and probably some other info as well.
Last edited by steven woodman; Oct 16th, 2008 at 1:32 pm.
I just read that the thing won't be operational till next Spring. They have to unthaw it to fix the electrical connection of one of the massive magnets.
yes, a machine that produces Ice cream so cold that it takes months to melt. I wonder, how long it would it take a 4L tub of ice cream at absolute zero to melt in 20 degrees celcius. I guess you would need the coefficient of the ice cream and probably some other info as well.
I spent an hour last night walking through what would be needed to calculate this - it is pretty ugly. Let's consider the ice cream is sitting on a perfectly insulated floor (absorbs no heat), the floor is actually a plane that can be considered infinite (no build up of insulating cold air), and the humidity is zero (so no moisture from air freezes to insulate the ice cream). Sigh, the Oxygen begins to liquefy (90.2K) and pool, then the Nitrogen begins to liquefy (77.36K) and solidify (63.15K) then the Oxygen begins to solidify (54.36K)- well, actually probably only gets to slush because the ice cream has warmed up a bit (I guess, we have to treat the ice cream like a large point source of cold cuz who wants to calculate the heat loss coefficient across the <crap, can we also put the ice cream in a sphere?> radius of ice cream). There is not much convection because the air is really cold and the frozen Nitrogen and slushy Oxygen are insulating the ice cream
Quote ...
(The thermal conductivity of liquid oxygen below 80 K and pressures up to 1 MPa has been measured using a horizontal, guarded, flat-plate calorimeter. The working equation of the calorimeter is based on the one-dimensional Fourier’s law. The gap between the calorimeter plates was measured in situ from a capacitance measurement. The cooling power to the calorimeter is provided by a two-stage Gifford–McMahan cryocooler. The absolute temperatures are measured using platinum resistance thermometers.)
Anyway, the math is way more than I want to play with; but it was fun thinking about it.
I was wondering
Last edited by GrimJack; Oct 18th, 2008 at 12:21 am. Reason: I forgot what I was wondering about
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