Stratus cloud
Ch.8, Weather
Lesson 3, Clouds and Precipitation
Objectives:
 Explore how clouds form.
 Identify causes and types of clouds and precipitation.
 Put in sequence the processes of the water cycle.
Cumulus cloud
Cirrus cloud
Fog
Precipitation
Water cycle
MAIN IDEA: water vapor and ice form clouds that produce precipitation.
1. How do clouds form?
a. Clouds are made up of tiny water droplets or ice crystals.
b. The air is filled with water vapor.
c. When air is cooled, the water molecules clump together around dust
and other particles in the air – they form droplets of water.
2. The three main types of clouds in the air.
a. Stratus Clouds – form in blanket-like layers
b. Cumulus Clouds – puffy clouds that appear to rise with a flat bottom
c. Cirrus clouds – form at high altitudes, and are wispy and feather like.
d. Nimbo or nimbus means “rain”
i. Nimbo can be added as a prefix to any cloud when it is raining.
e. Clouds can also be grouped into families by height.
i. Low clouds, middle clouds, and high clouds
f. Fog – is a cloud at ground level
3. What is precipitation?
i. Rain
ii. Snow
iii. Sleet
iv. Hail
b. Precipitation occurs when cloud droplets or ice crystals join together
and become heavy enough to fall.
i. They clump around particles of dust, that act as a nucleus.
When does precipitation occur?
When cloud droplets become heavy enough to fall.
What kind of cloud can produce hail? Why?
Clouds with vertical development; they have updrafts – winds that can hurl
ice crystals upward again and again creating hailstones.
4. The Water Cycle
When precipitati0on reaches Earth’s surface it:
a. Either evaporates right away into the atmosphere
b. Some of it runs off into rivers or streams – runoff
c. Most of it seeps into the ground – groundwater
d. The processes of the water cycle are
i. Evaporation
ii. Condensation
iii. Precipitation
5. What are the terms used to record cloud cover?
Clear, scattered clouds, partly cloudy, mostly cloudy and overcast.