CH. 2SEC. 5

PRECIPITATION

Objectives:1. What are the common types of precipitation?2. How is precipitation measured?

precipitation•any form of water that falls from clouds & reaches Earth’s surface

TRUE OR FALSE

•All clouds produce

precipitation.

precipitation•cloud droplets or ice crystals must grow heavy enough to fall thru air

types of precipitation

1. rain

2. sleet

3. freezing rain

4. hail

5. snow

rain• most common type of precipitation

• @ least 0.5 mm in diameter

drizzle

• rain < 0.5 mm

• mist-even smaller

• fall from stratus clouds

• raindrops freeze when touch cold surface (ground)

freezing rain

sleet•raindrops freeze as falling

•< 0.5 mm in diameter

Tiny ice pellets aretossed up and down incumulonimbus clouds,growing larger as theygain layers of ice.

Eventually the icepellets grow heavyenough to fall tothe ground as hail.

hail

hail• ice pellets add layers

of ice as carried up & down in cumulonimbus clouds during thunderstorms

• >5mm in diameter

snow•water vapor in cloud converts directly ice crystals

Weather Game

rain measured w/ rain gauge=

–open ended can or tube that collects rainfall

Rain Gauge

snowfall measured by:

1. using ruler or

2. melting collected snow & measuring depth of water it makes

drought

• long period of unusually low precipitation

cloud seeding• small planes used to sprinkle chemicals clouds to try to make rain

Precipitation Description