Visualize as you read. Draw and label important information in the space below each paragraph. Snowflakes The water vapor that rises from the surfaces of bodies of water, mixes with air and rises up into the sky. The reason it rises is because the mixture of water vapor and air is warm. Warm air rises.
Warm air rises because it is lighter than cold air.
The mixture of warm and air and water vapor keeps rising until it is high above the land. The higher it rises, the cooler the air around it becomes. Soon the mixture of water vapor and air reaches the upper atmosphere. The upper atmosphere is cooler than the air near the surface of the earth. It is filled with tiny particles.