Precipitation

• Chapter 16 section 5• November 29, 2007 T-4• Hannah, Steven, Gabby, Robbie

Vocabulary

• Precipitation: Is any form of water that falls from clouds and reaches Earth’s surface.

• Drought: Is a water shortage caused by long periods of low precipitation in a particular area.

• Rain Gauge: Is an open-ended can or tube that collects rainfall.

Rain

• Is drops of water that are at least 0.5 millimeters in diameter.

• Is the most common form of precipitation

• It is measured in a rain gauge.

Sleet

• Is raindrops falling through a layer of air below 0 degrees Celsius. As they fall, the raindrops freeze into particles of ice.

• Ice particles smaller than 5 millimeters in diameter is sleet.

Freezing Rain

• Is raindrops that freeze when they touch a cold surface instead of freezing when they touch the ground.

Hail• Are round pellets of ice

larger than 5 millimeters in diameter.

• Hail is only formed in cumulonimbus clouds during thunderstorms.

• During the thunderstorm strong updrafts carry the ice pellet up and down cold regions.

• Each time it passes a cold region a layer of ice is formed around it until it is heavy enough to fall.

Snow

• Is water vapor in clouds that is directly converted into ice crystals or snowflakes.

• Snow is measured in a rain gauge.

• Every snowflake has 6 sides and is unique.

Measuring Precipitation• Meteorologists measure

precipitation with rain gauges.

• A rain gauge is an open ended can or tube that collects precipitation.

• To measure how much precipitation is in a can put a ruler in it.

• For more precipitation add a funnel, that gives you ten times more of a certain kind of precipitation. When measuring it for accuracy divide by 10.

Controlling Precipitation

• When droughts occur airplanes sprinkle dry ice (solid carbon dioxide.) and silver iodide into clouds.

• Water vapor in the clouds condenses the particles of silver iodide forming rain or snow.

Georgia’s Drought

5 Facts About Georgia’s Drought

• The drought in Georgia is a level 4• Atlanta Georgia is 15 inches below their normal

precipitation .• There is about a three-month supply of water left

in Lake Lanier.• Atlanta Georgia is down to a 90 day supply of

water. • The drought responds to all counties in the north,

such as Muscogee, Spalding, and Lincoln counties.

What Must Happen Before Precipitation can Fall To The

Ground

Cloud droplets or ice crystals must grow heavy enough.