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Clouds
Humidity
• Humidity is amount of water in the air
• Warm air can hold much more water than cold air
• When there is as much water in the air as
possible, it is saturated. The temperature that
this happens is called the dew point
• http://www.brainpop.com/science/weather/hum
idity/
• http://www.youtube.com/watch?v=yyxc-81JDbo
Cloud formation
Warm air rises and
cools
Since cool air can
hold less water
than warm air…
…the air eventually
becomes saturated
(air reaches the
dew point)
Millions of
droplets of liquid
water collect to
form a cloud
Water vapor
condenses on
smoke, dust, salt
and other small
particles
suspended in the
air
Rain vs. Snow?
• At temperatures above freezing, water
condenses and falls as rain
• At temperatures below freezing, water
vapor changes directly to a solid, forming
ice crystals
Different Types of Clouds
• There are three
main categories
of clouds:
- Cumulus clouds
- Stratus clouds
- Cirrus clouds
Latin Root
Translation
cumulus
stratus
cirrus
nimbus
alto
heap
layer
curl of hair
rain
tall
Cumulus Clouds
• Puffy, white clouds with flat bottoms
• Form when warm air rises
• Generally mean fair weather
Cumulonimbus
• When cumulus clouds get bigger they
produce thunderstorms (cumulonimbus)
• Cumulonimbus clouds have updrafts that
can make them up to 30,000 feet tall
Stratus Clouds
• Form in layers
• Cover large areas of the sky and can block
out the sun
• Caused by a gentle lifting of a large body
of air
• When stratus clouds form near the
ground, it is called fog
Nimbostratus
• Nimbostratus clouds are dark and usually
produce continuous rain
Cirrus Clouds
• Thin, feathery, white clouds found at high
altitudes
• Formed very high in the troposphere
• Made of supercooled water droplets
• Form when the wind is strong
• Can indicate bad weather if they thicken
What Kind of Cloud?
Weird Clouds (just for fun)