Download Chapter 6 Weather Patterns

Chapter 6 Weather Patterns
Lesson 1
Clouds
Clouds form when water vapor in the air
condenses to form liquid water or ice crystals.
Condensation is the process in which water
molecules in water vapor become liquid water
because of a change in temperature.
The role of cooling
Prevailing winds can move air masses that are
cold or warm over regions. As air cools the
amount of water vapor it can hold decreases.
Water vapor then condenses and turns into tiny
droplets of water or ice crystals.
Dew point is the temperature at which
condensation begins.
The role of particles
Particles in the air are very important. In order
for clouds to form tiny particles must be present
in the atmosphere so that the water has a
surface on which to condense.
Most of these particles are salt crystals, dust, or
smoke. Without them clouds could not form.
Three main types of Clouds
Scientist classify clouds into three main types
based on their shape.
Cirrus
Cumulus
stratus
Cirrus clouds
Cirrus clouds are wispy feather looking clouds
that form at high altitudes and low temperature.
They look like feathery paint brush strokes high
above the atmosphere.
These clouds are made of ice crystals.
Cirrus Clouds
Cumulus Clouds
Clouds that look like cotton balls are called
cumulus.
These clouds form low in the atmosphere but
can extend very high upwards. If the cumulus is
low it indicates fair weather but if it’s large and
extend upward like a mushroom it means bad
weather and thunderstorms, these are then
called cumulusnimbus.
Cumulus Clouds
Stratus Clouds
Clouds that form in flat layers are know as
stratus. These clouds can cover the entire sky
and are dull, gray colors.