Q. If heat rises, why is there snow on top of mountains?
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A. It is true that hot air rises, but as it rises it also cools. In fact, air usually cools 10 degrees Celsius per kilometer, if there are no clouds and the atmosphere is fairly stable. Mount McKinley in Alaska is about six kilometers high. Say the air at the foot of the mountain was 10 degrees C. That's 50 degrees Fahrenheit. By the time it got to the top of Mount Kinley, it would be about minus-50 degrees C., or minus-58 degrees F.