3. Air Pressure
Warm air= expanding or rising air= leaves
behind L pressure
Cold Air=sinking air= leaves an area of H
pressure
4. W in d M o v e -
me n t
Uneven heating of the
earth’s surface causes
some areas to be
warmer than others.
As we know, warm al-
ways follows cold to
share it’s warmth-
when this happens in
the atmosphere, wind
5. What causes winds?
A wind is a horizontal Winds are measured
movement of air from by direction and speed
a area of high pres-
sure to an area of low The anemometer is
pressure the tool we use to
It is this difference in measure this
pressure that makes Wind chill=↑ cooling
the air move=wind
the wind causes
6. Water in the Atmosphere: Hu-
midity
Humidity: measure of the amount of water vapor stuck
between molecules in the air. The air’s ability to hold
water depends on the air temp
The hotter the air, the more water the air can hold
Cold air: molecules move slower so droplets of water
can start to stick together=condensation
Relative humidity: the amount of water vapor(%) com-
pared to the amount the air can hold- tool used is a
psychrometer.
100%=air is saturated
7. Cloud Formation
Clouds form when water vapor condens-
es on dust, salt particles in the air
The temperature in which condensation
begins is called the dew point
8. TYPES OF CLOUDS
Cirrus Clouds: wispy, feathery clouds
Form only at high levels, therefore are made of i
11. Types of Clouds
Stratus Clouds: clouds that form in flat
layers- cover all or most of the sky and
are low level clouds
12. Air Masses
Air masses are masses of air that have
the same characteristics of the surface
over which it develops
Pressure Systems
descending (going down)=H pressure
ascending (going up)=L pressure
