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> January 14, 2000:
Hour Two: Cold / Smallest Ice
Just how cold is "cold?" Is "cold" a frosty beverage? A Minnesota February? A winter in the Antarctic? Maybe your idea of "cold" is liquid nitrogen, at (-195.8 degrees Celsius), chilly enough to freeze a rubber ball till it shatters. Maybe you think liquid helium (-270 Celsius) is really cold, and anything warmer is for wimps. | But beyond any of those things, there's something that's still colder. Absolute zero, (-273.15 degrees Celsius), the temperature at which all molecules stop moving entirely, is really, really, cold. Ultimately cold. So cold that, while scientists have been able to reach temperatures within 20 billionths of a degree above absolute zero, they have never been able to get there -- and many think they never will. | 
The S.S. "Northwestern." On the Alaskan coast
after a storm. National Archives image. | It's not for lack of trying, though. Over the years, many scientists and engineers have explored what temperature really means, and have worked on ways to alter things' temperatures. Their research has resulted in more efficient engines, air conditioning, new materials, and even a new form of matter, the Bose-Einstein Condensate. On this hour of Science Friday, we'll talk with the author of a new book about history, heat, and the quest for low temperatures. | We'll also check in with researchers who say that they've made the smallest piece of ice possible - a hexagonal shape built out of just six molecules of water. A normal drop of water contains about 100,000,000,000,000,000,000 water molecules. The research may help the scientists examine how water molecules bond together, information of great interest to biologists, chemists, and pharmaceutical researchers. We'll find out how they made their small pieces of ice, and why. So call in! | 
A simulation of the structure of
the smallest possible piece of ice.
Image courtesy UNC-Chapel Hill. |
Guests:
Tom Shachtman
Author, "Absolute Zero and the Conquest of Cold"
New York, New York
Roger Miller
Professor, Department of Chemistry
University of North Carolina
Chapel Hill, North Carolina
Books/Articles Discussed:
Related Links:
Absolute Zero!
About Temperature
Introduction to Cryogenics
National Snow and Ice Data Center
This segment produced by:
Pat Hemminger
Web producer:
Charles Bergquist |