# ice rises

**URL:** <https://boards.straightdope.com/t/ice-rises/23689>\
**Category:** Factual Questions\
**Created:** [June 27, 2000, 4:03am UTC](https://boards.straightdope.com/t/ice-rises/23689 "2000-06-27T04:03:44Z")\
**Posts on this page:** 4\
**Page:** 2

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [June 30, 2000, 2:01am UTC](https://boards.straightdope.com/t/ice-rises/23689/21 "2000-06-30T02:01:18Z")

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Yes, it is possible to solidify helium, it’s just really, really difficult. IIRC, it takes something like .001 Kelvin and 1000 or so atmospheres of pressure-- it’s never been done at standard pressure.

The temperature of the phase transition from liquid to superliquid depends strongly on the isotope of the helium (He-3 has to get a lot colder); this is probably what jb\_farley is thinking of with the isotopes.

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**Author:** ![jayron\_32](https://avatars.discourse-cdn.com/v4/letter/j/41988e/32.png) [@jayron\_32](https://boards.straightdope.com/u/jayron_32)\
**Post date:** [June 30, 2000, 5:13am UTC](https://boards.straightdope.com/t/ice-rises/23689/22 "2000-06-30T05:13:20Z")

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zut said:

> [@](#):
>
> Care to enlighten me, jayron?

Sorry, I was asuming that Silo was refering to some system whereby molecules of air (nitrogen, oxygen, or argon) are trapped between the molecules of water in the ice latice, and I was highly skeptical of their existence. The translucence of ice is do to visible bubbles of air, which are decidedly macromolecular in nature (uh, you can see’em) and also aren’t trapped by ice’s crystal latice, they are extracrystalary also (is that a word?) Sorry about the confusion.

And chronos, I defer to you on solid helium. I don’t know it all, and appatently you know more in this case.

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**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\
**Post date:** [June 30, 2000, 4:09pm UTC](https://boards.straightdope.com/t/ice-rises/23689/23 "2000-06-30T16:09:00Z")

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Ahh. OK, **Jayron**. I interpreted **Silo’s** comment the same as you did. I just got confused when you said you were skeptical of the existance of _any_ “theoretical” trapped air. Thanks for the clarification.

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**Author:** ![light\_strand](https://avatars.discourse-cdn.com/v4/letter/l/a6a055/32.png) [@light\_strand](https://boards.straightdope.com/u/light_strand)\
**Post date:** [June 30, 2000, 4:56pm UTC](https://boards.straightdope.com/t/ice-rises/23689/24 "2000-06-30T16:56:53Z")

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An interesting aside to this conversation, is why a lake freezes from top to bottom.

As water cools it becomes more dense, thus the colder water sinks to the bottom and the less dense warmer water rises to the top. This convection continues until the water is a homogenous 4 degrees C. Below this temp the density of water begins to decrease with decrease in temperature so that it no longer sinks. On further cooling the water begins to freeze at the surface. The ice layer doesn’t sink because it’s less dense than the liquid and acts as a thermal isolator for the water below.

Ice fishermen rejoice!

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