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Stockholm University: The Arctic Fox
Not only does this comprehensive site present a wealth of factual information on the Arctic fox but also delves into exploitation of this animal in North America, Russia, Iceland, and Greenland.
Florida State University
Florida State University: Magnet Lab: Dilution Refrigerators
Dilution fridges owe their cooling power to the incredible element helium. This animation illustrates how dil fridges exploit the element's properties to make things very, very cold.