Weather
Lesson #6: Precipitation - Clouds
Time Frame: 60 minutes
Learning Standards:
Science
Earth and Space Science: Weather
1) Explain how air temperature, moisture, wind speed and direction, and
precipitation make up the weather in a particular place and time.
2) Distinguish among the various forms of precipitation (rain, snow, sleet,
and hail), making connections to the weather in a particular place and
time.
Skills of Inquiry
 Ask questions and make predictions that can be tested.
Student will be able to:
1) Describe precipitation and explain the different types of precipitation.
2) Explain how clouds form and the characteristics of different types of
clouds.
Focus Activity: Review the water cycle with the class. Ask students what
happens to the water that evaporates from the oceans, rivers, lakes, and other
bodies of water? Why does this water evaporate? Where does this water go?
Introduction: Review with students that weather occurs because of the
interaction between the sun, atmosphere, and the earth. Explain that water in
the atmosphere (from the water cycle) falls back to the earth as precipitation.
Precipitation is any form of water falling from the sky and may include rain, snow,
sleet, or hail. Discuss the differences between these types of precipitation
(briefly).
Activities:
1) Explain that water that evaporates from the surface of the earth goes into
the atmosphere and then cools. When the water vapor cools it condenses
(from a gas back to liquid or solid form) and small droplets form around
tiny pieces of dirt and dust. A cloud is a large collection of water droplets
or ice crystals. As long as the cloud is warmer than the air around it, it will
float.
Additional Cloud Background Information:
Why are clouds white?
Clouds are white because they reflect the light of the sun. Light is made
up of colors of the rainbow and when you add them all together you get
white. The sun appears a yellow color because it sends out more yellow
light than any other color. Clouds reflect all the colors the same amount so
they look white.
Why do clouds turn gray?
Clouds are made up of tiny water droplets or ice crystals, usually a mixture
of both. The water and ice scatter all light, making clouds appear white. If
the clouds get thick enough or high enough all the light above does not
make it through, hence the gray or dark look. Also, if there are lots of other
clouds around, their shadow can add to the gray or multicolored gray
appearance.
2) Conduct a demonstration in front of the class that shows how clouds form.
Open a large plastic bag and scoop in some air from the room, seal it
tightly shut, put the bag in the freezer for 5 minutes, take it out of the
freezer and blow into it, quickly seal the bag and shut it again, observe
what happens, explain why and how it forms a cloud. (Alternatively, you
can place a bag in the freezer before class so you don’t have to wait 5
minutes). Where does the water in the cloud come from? What happens
when my warm breath meets the cold air of the bag? What is this called?
(Condensation).
3) Ask the students to think about the clouds that they see (look at the
window if possible). Try to get the students to describe how clouds are
different and similar as an introduction to types of clouds. Use the cloud
poster (or cloud diagrams) provided to teach students the names of
different clouds and what they look like. Discuss how the different types of
clouds can be used to predict different types of weather.
a. Cirrus clouds are the most common type of high clouds. They are
made of ice and look thin and wispy. The wind often blows them
into long streamers. Cirrus clouds are usually white and predict fair
to pleasant weather. By watching the movement of cirrus clouds
you can tell from which direction weather is approaching.
b. Alto clouds are middle level clouds that are made of water
droplets and appear as gray, puffy masses, sometimes rolled out in
parallel waves or bands. Alto clouds often indicate approaching
storms or thunderstorms.
c. Stratus clouds are low, uniform grayish clouds that often cover the
entire sky. They resemble fog that doesn't reach the ground. Light
mist or drizzle sometimes falls out of these clouds.
d. Cumulus clouds are white, puffy clouds that look like pieces of
floating cotton. Cumulus clouds often indicate fair weather. The
bottom of each cloud is flat and the top of each cloud has rounded
towers. But, these clouds can grow and develop into thunderstorm
clouds (cumulonimbus clouds) that produce rain, sleet, hail, snow,
and even tornadoes.
4) Working individually or in small groups direct students to make a poster
showing the different types of clouds. Allow students to use the cloud
diagrams provided to remember the different types of clouds.
a. Give each group some cotton balls, glue, a piece of black
construction paper, and a white writing implement (crayon or
colored pencil). Remind them that some clouds are found up high
and some are found down low and to place their cotton ball clouds
accordingly. Once students have glued down the cotton ball clouds
they should label them with the correct name.
b. If time permits, allow students to present their cloud posters to the
class and discuss what types of weather the different clouds
indicate.
5) Discuss the weather data collected as a class. What do students notice
about the types of clouds and the precipitation or weather? Do certain
types of clouds indicate rain or snow? Do some types of clouds seem to
indicate fair weather?
Closure: Discuss the following questions as a class. What is a cloud made of?
How does a cloud form? What are some different types of clouds? How can
clouds be used to make weather predictions?
Assessment: Participation in class activities and discussions, completed cloud
pictures and labels
Resources and Materials: Water cycle diagram, Ziploc bag, freezer (not
provided), cloud diagrams, black construction paper (not provided), cotton balls,
glue (not provided), white crayons or colored pencils (not provided)
Optional Activity to Identify Cloud Types: This can be used with the daily
weather observations. Please see attached papers. This activity requires
student copies, scissors (not provided in kit), and brass fasteners.