1. Weather Variables: Air Pressure and Wind
Mr. Cloud
Earth Science

2. Air Pressure (barometric)
Is the pressure due to the weight of the overlying atmosphere pushing down on any given area
At sea level about 14 lbs/in2 of air pressure is constantly pressing upon our bodies!
Instrument used to measure air pressure?
Barometer

3. Barometer

4. “The Sun is the Star of Our Breezes”
Discussion Questions:
Identify the force behind the winds of Earth.
What happens to air that is warmed? Cooled?
In what direction does wind always flow? What does the author compare it to?
What Earth motion directly affects the direction of global wind patterns?
Explain how a sea breeze and land breeze develops.

5. Wind H L Wind: the horizontal movement of air at Earth’s surface
Wind is caused by differences of air pressure
Wind always blows from regions of high pressure to regions of low pressure
H L

6. Wind Instruments Anemometer: measures wind velocity Wind Vane:
measures wind direction

7. Isobars: lines that connect equal values of air pressure
Using the synoptic weather map:
Where is wind velocity the greatest?
Where is wind velocity the slowest?
How do you know?