Precipitation

Studying Precipitation The atmosphere is a blanket of gases that surrounds Earth. One of the gases in the atmosphere is water vapor. It rises from oceans, lakes, and other bodies of water when the Sun warms them. Water vapor cools as it rises. Then, it condenses and forms tiny drops of water. When the drops become large enough, they fall as rain or snow. Water that falls to Earth in solid or liquid form is called precipitation. Earth's atmosphere is divided into layers. Most clouds form in the lowest layer, closest to Earth. Did you know that 4 trillion gallons (15 trillion liters) of precipitation fall on the United States every day? Here are more interesting facts about precipitation. • Ten inches (30 centimeters) of snow contain as much water as 1 inch (2 cm) of rain. • Cherrapunji, India, holds the record for the most rainfall in 1 year—more than 80 feet (24 meters). • At all times, the atmosphere contains enough water for 1 inch (2.5 cm) of rain to fall on Earth. Earth is not the only planet where frost forms. Frost sometimes covers the ground on Mars, too. Very little precipitation falls at the North Pole.The snow that falls at the North Pole does not melt. Types of Precipitation There are many types of precipitation. Rain falls when the weather is warm. Rain becomes snow when the weather is cold. A B C D dew: water vapor that condenses on plants after a cool night frost frozen water vapor or dew that forms when condensation freezes sleet melting snow or freezing rain hail: balls of ice that form when the temperature is just below freezing A B Six-sided When cooled, water vapor condenses into water drops. In temperatures below freezing, these water drops become snowflakes. Each snowflake is made from tiny pieces of ice that stick together. I l I l I All snowflakes have six sides. Although snowflakes may look the same, no two snowflakes are alike. Each has a different pattern of frozen water molecules. I I I I I Ml ii .1 r , ..I I I r 1 I An average snowflake falls at a speech of 3 miles (5 kilometers) per hour.! !' I I Water Vapor Clouds and fog are water vapor. Clouds form when water vapor condenses around tiny pieces of dust. Fog is a thick mist of water vapor in the air, near the ground. Sometimes, water droplets join together to form larger drops of water. These drops of water fall to the ground as precipitation. • Falling raindrops are shaped like hamburger patties. They are squashed balls with flat tops and bottoms. >me people believe that stepping on a spider causes in. For many years, people have tried to predict the weather by watching how animals act. ^ H Here are some other signs that people believed were a sign of rain. • bees returning to their hives • ants building barriers around their nests cattle lying down in the field flies collecting on window and door screens butterflies flying from the southwest cats washing their ears Storms Storms have strong winds and precipitation. A blizzard is a bad winter storm that can last for many hours. During a blizzard, strong winds blow large amounts of snow through the air. Freezing rain falls during an ice storm. The air is usually warm enough for rain, but the ground is very cold. Streets and sidewalks bec