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Freezing

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Jenny
216876.  Thu Oct 04, 2007 1:32 pm Reply with quote

Lots of potential stuff in this topic, but my interest was piqued by post 216860 and the link between freeze-drying and the Incas.

 
Flash
277427.  Thu Feb 14, 2008 2:41 pm Reply with quote

Freezing, Fingers and Frostbite - Sir Ranulph Fiennes' description of self-medicating his frostbitten fingers:
Quote:
The dead ends of my fingers were very black, and every time I touched one of them against something it was agonizing. Eventually I thought, 'Well, why don't I get rid of them?' So I used a Black & Decker vise and a saw in the toolshed. It wasn't painful, but going through the bones was quite difficult. It felt better afterward, since I was much less likely to hit things with my fingers.

What It Feels Like, a collection of articles from Esquire Magazine, p20

 
dr.bob
277626.  Fri Feb 15, 2008 5:09 am Reply with quote

He was interviewed on Top Gear, when he was their "star in a reasonably priced car". He said he began by trying a hacksaw, but that didn't work, so he used a "micro blade" instead (whatever that is).

He also said that his physio told him he'd done a very good job of it, but he'd annoyed his surgeon because he'd made his job harder than if he'd left the dead ends of his fingers where they were.

Full interview on YouTube. The discussion about his frost bite begins at the 5:29 mark.

 
Frederick The Monk
282333.  Fri Feb 22, 2008 5:15 am Reply with quote

The coldest temperature ever created in the lab is 450 picoKelvin. It was produced in a Bose-Einstein condensate of sodium atoms at MIT by Wolfgang Ketterle and announced in September 2003.

http://physicsworld.com/cws/article/news/18214

The hottest temperature created in the lab is more than 2 billion degrees Kelvin, which is hotter than the interior of our Sun, which is about 15 million degrees Kelvin. The feat was accomplished in the Z machine at Sandia National Laboratories. The result was announced in the February 24th issue of the journal Physical Review Letters in which the experimenters also rather disarmingly point out that they have no idea how they managed it.

http://www.livescience.com/technology/060308_sandia_z.html

 
WB
285307.  Tue Feb 26, 2008 1:56 pm Reply with quote

A man produces more heat per kilogram than the sun

 
Flash
285308.  Tue Feb 26, 2008 1:58 pm Reply with quote

Speak for yourself.

 
dr.bob
285557.  Wed Feb 27, 2008 4:12 am Reply with quote

The power output of the Sun is surprisingly low given its size. Presumably this is 'cos the vast bulk of material outwith the central core is not producing any energy.

With a power output of 4 x 10^26 Watts and a mass of 1.9891 x 10^30 kg, the Sun only produces 0.0002 W/kg.

By contrast, a low energy light bulb I have here in my room produces 11W of power, and weighs 55g. This gives a power to mass ratio of 200 W/kg, or one million times greater than the Sun.

 
eggshaped
294718.  Wed Mar 12, 2008 10:12 am Reply with quote

Wim Hof is known as "the ice man". He has an amazing ability to withstand the cold.

In January of 1999 he traveled 100 miles north of the Arctic Circle to run a half-marathon in his bare feet.

He holds the Guinness World Record for the longest amount of time swimming under the ice of the North Pole.


This isn't him.

http://abcnews.go.com/Health/story?id=4393377&page=1

 
dr.bob
294837.  Wed Mar 12, 2008 12:07 pm Reply with quote

Odd. The report says that he set his North Pole swimming record in 2002. However, last year British Explorer Lewis Gordon Pugh was reported as being "the first person to swim at the North Pole."

http://wcco.com/health/Lewis.Gordon.Pugh.2.286585.html

 
WB
297539.  Mon Mar 17, 2008 2:11 pm Reply with quote

Cornelius Drebbel, a mad Dutch inventor, demonstrated an air-cooling machine to his patron James I in the summer of 1620. No pictorial reference exists of how he did this, but it must have been on a largish scale to make a difference to Westminster Hall. It presumably involved fans and ice. He certainly developed a rudimentary thermostat using Mercury to control the temperature of a hen’s egg incubator. He is mentioned in Pepys’ diary and is known as the man who built the first working submarine.

 
WB
297541.  Mon Mar 17, 2008 2:12 pm Reply with quote

Francis Bacon, the father of modern science, stuffed a chicken full of snow to see whether the meat stayed fresh longer. Unfortunately he caught Bronchitis from going out in the cold to collect the snow and died a month later from Pneumonia. The experiment is supposed to have taken place in Pond Square, by Highgate Cemetery. Soon after Bacon died stories started to circulate of appearances of a ghost chicken in Pond Square. Sightings continued even during the Blitz. Wags have termed it ‘the poultrygeist’.

 
WB
297543.  Mon Mar 17, 2008 2:13 pm Reply with quote

Francis Bacon noted the so-called Mpemba Effect – that warm water freezes faster than cold. The effect is named after a Tanzanian schoolchild who first noted it in 1963 and published his experimental results in 1969 jointly with a university don Denis G. Osborne. Straight Dope poo-poo’s the theory, saying in their experiment water at 38oF froze faster than water at 125oF. New Scientist bods back the idea though (not surprisingly as they broke the story). The reasons for the effect appear to be many – from the simple physical thing that a warm ice tray might melt itself into the frost, getting more contact with cold surfaces. Or more complicated physics of un-heated water having more solutes and therefore a lower freezing point (as in salt water). It would appear that quite a lot of serious science has now been done on this, so I would say it’s for real, but the answer is not simple. “How to Fossilise your Hamster” has a good chapter on it.

 
WB
297544.  Mon Mar 17, 2008 2:13 pm Reply with quote

Water does not automatically freeze at 0oC, even at atmospheric pressure. Water can be ‘supercooled’ whilst remaining liquid to –42oC if there are no impurities to seed crystal formation. There is good film of supercooled mineral water freezing instantly when disturbed at http://f0rked.com/articles/supercooling.

 
WB
297546.  Mon Mar 17, 2008 2:14 pm Reply with quote

There are fourteen recognised different crystalline forms of ice, formed at different temperature/pressure ratios. All ice formed at normal atmospheric pressure on Earth is hexagonal ice Ih. A small amount of cubic ice Ic forms in the upper atmosphere.

 
WB
297547.  Mon Mar 17, 2008 2:14 pm Reply with quote

Q. How can you make a glass out of water?
A. Freeze it very fast.
When water is cooled very rapidly (106 K/s), then crystal nucleation is avoided and the water freezes as a glass (non-crystalline solid). This process is called hyperquenching. Interestingly glassy water is almost certainly the most common form of water in the universe as it is the bulk of matter in comets.

 

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