Tumblehome Talks

Science Enrichment at Home and After School

Cold Snap: Cool Facts About Ice and Dry Ice

by Penny Noyce

All over the U.S. the weather is serving up sub-zero weather, so let’s talk about ice. Here are ten fascinating facts:

1)  Regular ice is frozen water.  Dry ice is frozen carbon dioxide, and it’s very cold, below -78 degrees Celsius.  Unlike water, carbon dioxide does not go though a liquid stage as it cools from a gas stage to a solid stage.  Similarly, dry ice doesn’t melt.  Instead, it changes directly from solid into a vapor or gaseous form. This change is called sublimation.

The New England Ice Storm of 2008

The New England Ice Storm of 2008

2)  Ice covers about 10 percent of the Earth’s land mass and about 7 percent of its oceans.

3)  Water is one of very few compounds in the universe that expands as it cools from liquid to solid form.  That’s why ice floats on water.  It’s also why a closed bottle of water, left out in the freezing cold, can push its top off or even burst.

Ice Hotel

Ice Hotel

4)  The reason ice looks cloudy is because of tiny air bubbles trapped in the water as it freezes.  You can actually get clearer ice cubes by starting off with warm or hot water, which has less dissolved air in it than cool water coming straight from a frothy faucet.

5) The water at the bottom of the deepest oceans is actually -4 degrees Celsius.  Why is it still liquid when it’s below freezing?  Remember, water has to expand to form ice. The water at the bottom of the ocean, crushed under all that water pressure, can’t expand to form ice crystals, even though it’s very cold.

6) Dry ice sinks in water.  Its specific gravity (density compared to water) is about 1.5.  If you drop it in water, though, you’ll get wild bubbling and an outpouring of what seems to be cold steam.  That’s why dry ice is great to cool your punch at a Halloween party.

Dry ice

Dry ice

7) The ice in comets is not the nice crystalline structure we know.  Instead, it’s an amorphous (without form) random arrangement of molecules known as “glassy ice.”  On earth, glassy ice can only form when water is rapidly cooled to -137C.

8) Sea ice is important to regulating global temperature, because the white, bright ice reflects back 80% of the light that hits it and helps to keep the ocean cool.  Once sea ice melts, the dark-colored ocean absorbs ninety percent of the sunlight, leading to greater warming.

9) Algae grow between the cracks in sea ice and even on the underside of the ice, providing food for tiny shrimp-like krill throughout the dark, cold arctic winter.

10) In the science fiction book Cat’s Cradle by Kurt Vonnegut, ice-nine is a special form of ice crystal that causes any water it comes in contact with to solidify immediately into more ice-nine.  Throwing a tiny piece of ice-nine in the ocean could instantly dry up all the water in the world.

11)  Bonus fact:  In Tumblehome Learning‘s The Ice Castle: An Adventure in Music, Ivan and Daphne are stuck in the Land of Winter, where social status and opportunity are determined solely by how well a person sings.  Spring will come to the Land of Winter only when the Diva sings her way free of a castle built of ice.

51PizqgmdPL._SS500_For more cool facts on ice, check here.

For facts on diamonds, try here.

And for facts on glass, visit here.

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One comment on “Cold Snap: Cool Facts About Ice and Dry Ice

  1. Penny
    January 27, 2013

    New evidence shows that when the dry ice at Mars’s north pole sublimates, the resulting carbon dioxide gas carves changes in the sand dunes there.

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