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boiling water instant freeze

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Post by Guest Sat Dec 28, 2013 2:05 pm


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Post by Marathadi-Saamiyaar Sat Dec 28, 2013 2:18 pm

Brigadier HK (Retd) wrote:

What do you think happens when "smoke" comes out of chimneys in cold regions at -5 C ?

You never noticed it on the NYC skyline during Jan and Feb when you lived here?

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Post by Guest Sat Dec 28, 2013 2:33 pm

Marathadi-Saamiyaar wrote:
Brigadier HK (Retd) wrote:

What do you think happens when "smoke" comes out of chimneys in cold regions at -5 C ?  

You never noticed it on the NYC skyline during Jan and Feb when you lived here?
LOL! good question. i never noticed it. i suppose white smoke at -5 or 20 would look the same? how about cigarette smoke?

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Post by Marathadi-Saamiyaar Sat Dec 28, 2013 3:15 pm

Brigadier HK (Retd) wrote:
Marathadi-Saamiyaar wrote:
Brigadier HK (Retd) wrote:

What do you think happens when "smoke" comes out of chimneys in cold regions at -5 C ?  

You never noticed it on the NYC skyline during Jan and Feb when you lived here?
LOL! good question. i never noticed it. i suppose white smoke at -5 or 20 would look the same? how about cigarette smoke?

Not ciggy smoke...thre is not much water vapor in it.

Observe when a car is started first time in the morning on a cold morning. you will see whitish smoke out of its exhaust only for a few minutes (if you keep your hand at the outlet it will become wet immediately.) If the temperature is around 5 C or less you might see that.

why doesn't the car exhaust give out that whitish smoke after 5 minutes???? Now that is a question for undergraduate students.(Not even Koran or Upanishads will give the answer for this).

(remember actual white smoke from car exhaust is real bad news).

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Post by Guest Sun Dec 29, 2013 1:54 am

Marathadi-Saamiyaar wrote:
Not ciggy smoke...thre is not much water vapor in it.

Observe when a car is started first time in the morning on a cold morning. you will see whitish smoke out of its exhaust only for a few minutes (if you keep your hand at the outlet it will become wet immediately.) If the temperature is around 5 C or less you might see that.

why doesn't the car exhaust give out that whitish smoke after 5 minutes???? Now that is a question for undergraduate students.(Not even Koran or Upanishads will give the answer for this).

(remember actual white smoke from car exhaust is real bad news).
good observations! i suppose the exhaust pipe is full of condensed water (from the humid air) which is immediately expelled upon starting the engine.

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Post by MaxEntropy_Man Sun Dec 29, 2013 11:18 am

an interesting question is since it is being cooled so rapidly (enormous rates of heat transfer to remove that much enthalpy), i wonder if the flakes formed are crystalline or if they are amorphous and glass like rather than crystalline.
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Post by Marathadi-Saamiyaar Sun Dec 29, 2013 1:18 pm

MaxEntropy_Man wrote:an interesting question is since it is being cooled so rapidly (enormous rates of heat transfer to remove that much enthalpy), i wonder if the flakes formed are crystalline or if they are amorphous and glass like rather than crystalline.

The video is similar to "freeze-drying" much like the sleet you are expected to get tonite in your area. The guy could dump the hot water through nozzle and the instant droplets will be so small, they might just float as one sees the "smoke" from the chimneys in winter. In fact one can control the size, shape and character of these "droplets" by properly sizing and manipulating the pressure.

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Post by Obnoxious Sun Dec 29, 2013 1:51 pm

MaxEntropy_Man wrote:an interesting question is since it is being cooled so rapidly (enormous rates of heat transfer to remove that much enthalpy), i wonder if the flakes formed are crystalline or if they are amorphous and glass like rather than crystalline.
IT would take sometime to freeze, if the water was in the vessel. As he is throwing the water, water becomes droplets & freezes quicker.

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Post by MaxEntropy_Man Sun Dec 29, 2013 2:00 pm

Obnoxious wrote:
MaxEntropy_Man wrote:an interesting question is since it is being cooled so rapidly (enormous rates of heat transfer to remove that much enthalpy), i wonder if the flakes formed are crystalline or if they are amorphous and glass like rather than crystalline.
IT would take sometime to freeze, if the water was in the vessel. As he is throwing the water, water becomes droplets & freezes quicker.

yes, but my question went beyond that. the crystalline state, namely ice, which has long range periodic order forms through a process known as nucleation and growth which requires longer length scale atomic (molecular) motion, also known as diffusion. this usually takes some time. when matter goes from a liquid to a solid state very rapidly, there is insufficient time to form the crystalline state and hence freezes in an amorphous (disordered) state. this is basically a very high viscosity liquid also known as glass. since the freezing in this video is occurring very rapidly, i was idly musing whether the state of matter that is formed from the rapid freezing is crystalline or amorphous. that it freezes rapidly is quite evident from the video. i am sure somebody has looked into it. there's probably a slew of papers on it.
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