Sudha Prathikanti, age 11, of Montgomery, Alabama, for her question:

Is it true that no two snowflakes are alike?

Nobody can prove that no two snowflakes are exactly alike. After all, how could a person catch all the snowflakes and compare them? As you know, a snowflake melts in your warm hand before you can study it in detail. Besides, its delicate patterns are so tiny that you have to magnify them under a microscope. Even so, we can be fairly sure that each snowflake is different from all the others.

A snowflake is made from zillions of mini ice crystals arranged with zillions of mini air pockets. They are six sided crystals that slither around to form six sided patterns. It would be almost impossible to arrange the same pattern twice. Besides, the lacy arrangements are changed by the weather. If two patterns started out exactly alike, a slight puff of cool air could change one of them to a different design. So there is not much chance that two snowflakes have exactly the same lacy design from start to finish.