Pitch drop experiment

Explorer said:
Sol said:
Water is really freeky stuff, and even if logically it should be a gas it is still very dense... More dense than ice...

Keyword: Phase

Liquid water is denser than solid water (ice) because hydrogen hydroxide (HOH, H2O) expands as it enters its solid phase -- which defies the norms of all other molecules. Water at a temperature of somewhere about 1.5ºC ~ 2ºC is found at the bottoms of deep fresh water lakes in cold climates because water at this temperature is at its highest density, and the colder ice is found floating on top of the lake.


I'ts probably a good thing too, or else all the fishies and anything else in lakes would get frozen and be dead in the winter.

Stereodude
 
It is also interesting to note the atmospheric pressure/boiling point issue with water.
At sea level water boils at 100C (213F) but when elevated to 3050M (10,000ft) it boils at 90C (193F) although I suspect this would also be the case with other liquids/gases.
 
slo crostic said:
It is also interesting to note the atmospheric pressure/boiling point issue with water.
At sea level water boils at 100C (213F) but when elevated to 3050M (10,000ft) it boils at 90C (193F) although I suspect this would also be the case with other liquids/gases.

Yes, indeed it is. Boiling point is the point at which the vapor pressure of the liquid exceeds the pressure of the surrounding environment. As you raise the temperature of a liquid the vapor pressure goes up, and the temperature at which the vapor pressure exceeds the ambient air pressure is what is commonly referred to as the boiling point. Naturally, at higher altitudes the air pressure is less, so the boiling point is lower. Water at room temperature has a vapor pressure of 0.3 psi(normal atmospheric pressure is 14.7 psi). This means water at room temperature will boil at approximate 100,000 feet altitude, and in a complete vacuum liquid water(or any liquid) will boil at any temperature(unless it is frozen solid). This is why materials used for lubrication is outer space must be solid(i.e. Teflon). Any greases will eventually vaporize(or outgas as the phenomenon is usually called).
 
Stereodude said:
'ts probably a good thing too, or else all the fishies and anything else in lakes would get frozen and be dead in the winter...

Since you're in Michigan, ever notice how most lakes during the beginning of winter start "churning?" That's the displaced water coming up to the surface, getting chilled and becoming more dense, then going back down towards the bottom and displacing slightly warmer water which comes to the surface to be chilled... etc.


BTW, ever see goldfish "frozen in place" in a pond in the wintertime, just to see the same ones swimming around like nothing happened later on in spring? Kinda weird.

 
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