A PPT on cloud formation and a series of why and how questions about clouds. Types of clouds are listed at the end of the lesson.

1. Cloud formation
Inquiry: What, how, and why?

4. All air contains water, but near the ground it is usually
in the form of an invisible gas called water vapor.
When warm air rises, it expands and cools. Cool air
can't hold as much water vapor as warm air, so some of
the vapor condenses onto tiny pieces of dust that are
floating in the air and forms a tiny droplet around each
dust particle. When billions of these droplets come
together they become a visible cloud!

6. Rising Air
• Imagine a block of air (air parcel) rising
upward through the atmosphere.
• As the air parcel rises it expands!
• This expansion causes the temperature of the
air parcel to decrease.

7.  Condensation
Rising Air
• Imagine a blockair rises the atmosphere is
As the block of of air (air parcel) rising
upward through the atmosphere.
cooler.
• As the air parcel rises it expands! air,
Cold air holds less water than hot
• therefore, the water vaportemperature of the
This expansion causes the gets closer
(condenses) decrease.
air parcel to & cloud droplets form!


8. Formation…
• This can happen through many different ways
– Convection Currents
– Lifting
– Frontal Activity

9. Convection Currents

10. Lifting (help of mountains)

11. Frontal Activity (Warm & Cold)

13. Why do clouds
float?
A cloud is made up of liquid water droplets. A
cloud forms when air is heated by the sun. As
it rises, it slowly cools it reaches the
saturation point and water condenses,
forming a cloud. As long as the cloud and the
air that its made of is warmer than the
outside air around it, it floats!

14. How do clouds
move?
Clouds move with the wind. High
cirrus clouds are pushed along by the
jet stream, sometimes traveling at
more than 100 miles-per-hour. When
clouds are part of a thunderstorm
they usually travel at 30 to 40 mph.

15. What are the different
types of clouds?
There are many different types of clouds and
different ways to identify them. This type of
identification classifies clouds by the height of
the cloud base.
• High Level Clouds
• Mid-Level Clouds
• Low-Level Clouds
• Miscellaneous Clouds

17. • HIGH ALTITUDE CLOUDS:
• Cirrocumulus – Puffy, patchy look with spaces
• Cirrostratus – light gray or white, thin, covers
most of the sky.
• Cirrus – thin wispy and feathery appearance

18. High Altitude clouds ...
Cirrus clouds are ice
clouds. They can look
like delicate white
feathers or streamers.
They are always more
than five kilometers
up where the
temperature is below
freezing, even in
summer! Wind
currents twist and
spread the ice crystals
into wispy strands.

19. • MIDDLE ATLTITUDE CLOUDS:
• Altocumulus – puffy, patchy look with spaces
• Altostratus – light gray and uniform in
appearance. Covers most of the sky.

20. • LOW ATITUDE CLOUDS:
• Cumulus – puffy, looks like cotton balls/popcorn
• Stratus – light/dark gray and uniform. Fog!
• Stratocumulus – irregular masses, rolling or puffy with
spaces.
• Nimbostratus – dark gray with precipitation falling from
them. Bases are hard to see b/c of rain.
• Cumulonimbus – large clouds w/ dark bases and tall
billowing towers. Also known as “Thunder Clouds”

21. LOW ATITUDE CLOUDS (close up)

22. LOW ATITUDE CLOUDS (close up)

23. LOW ATITUDE CLOUDS (close ups)

24. Cumulonimbus clouds…
…are a sure
sign of bad
weather Rain,
thunder,
lighting,
hail, and
possibly
tornadoes!