Nor did many think of the statistical improbabilities involved. I have heard those who should certainly know better try to salvage this myth. If you consider their molecular structure, then no two snow flakes are the same shape. In that case, no two ping -pong balls are the same shape either. Nor ball bearings .
Warm air rises, cool air is sucked in to replace it.
This myth requires a combination of prescientific notions, as well as reversal of cause-effect relationships. First we need to know what the words, warm and cool mean. If you ask your students, you will find that most of them think of them as specific, rather than comparative, temperatures. By probing you can establish that, to most students, warm is a temperature higher than the observer s skin temperature, and cool is lower than the observer s skin temperature. And of course skin temperature changes.