To see roughly how much ocean water there is on the globe, draw a circle on a piece of paper, and use a pencil and ruler to cut it into quarters. Colour one of the quarter circles brown and the rest blue. The brown part represents all the seven continents put together, and the blue area represents all the four oceans. All seven continents would fit into the largest ocean, the Pacific. How large is the Pacific? It contains 46% of the earth's water.

Precipitation is another part of the hydrologic cycle. Precipitation begins when water vapor condenses and falls toward the earth as ice, snow, rain, or freezing rain. Ice crystals, tiny hexagonal, or six-sided, crystals found high in the atmosphere, are the first stage in the formation of snowflakes. If an ice crystal continues to grow larger, a snow crystal is formed. Snow crystals, like ice crystals, are six-sided, but they have a more complex shape. A snowflake forms when two or more snow crystals become joined. Some snowflakes may be made of several hundred snow crystals that have come together.
In 1880 Wilson Alwyn Bentley, a 15-year-old boy who lived in Jericho, Vermont, began examining snowflakes through a microscope. He noticed that snowflakes were crystals. Although he was not the first person to notice this, what he did five years later had never been done before and led to a lifelong study of snowflakes. In 1885 Bentley attached a special camera to his microscope and took the first successful photographs of snowflakes. "Snowflake' Bentley, as he came to be called, photographed many thousands of snowflakes during the 40 years that followed, and he never found two
that were identical.
Snowflakes come in many sizes. Snow crystals and flakes that form in especially cold air, where there is less water vapor available, tend to be small. Warmer air, with more available moisture, tends to favor the formation of large, wet flakes. These flakes frequently collide with other flakes and stick together while floating downward, sometimes forming snowflakes with diameters as large as 2 inches (5 cm).

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