BOB DOUGHTY: When snow crystals stick together, they produce snowflakes. Snowflakes come in different sizes. As many as one hundred crystals may join to form a snowflake larger than two and one-half centimeters. Under some conditions, snowflakes can form that are five centimeters long. Usually, this requires near-freezing temperatures, light winds and changing conditions in Earth's atmosphere.
基于1个网页-相关网页
应用推荐