1. Air Pressure – the force that air exerts on the surface of Earth per unit of area

2. Average Air Pressure at Sea Level 1 bar 1013 millibars 14. 7 psi 29
Average Air Pressure at Sea Level 1 bar 1013 millibars 14.7 psi in Hg 760 mm Hg
The normal range of the Earth's air pressure is from 980 millibars (mb) to 1050 mb.

3. MERCURY BAROMETER

4. ANEROID BAROMETER

5. ANEROID BAROMETER

6. Air pressure varies due to:
altitude
temperature
water vapor

7. Air Pressure 
Temperature / Humidity / Elevation 

10. N2 O2 N2 N2 N2 O2
H2O N2 N2 N2

11. Atomic Masses (Rounded off) H = 1 amu N = 14 amu O = 16 amu

12. N2
28 amu O2 N2 N2 N2 O2
32 amu
H2O N2
28 amu N2 N2

13. H2O
18 amu O2 N2 N2 N2
H2O
18 amu
H2O
H2O
18 amu N2 N2

14. WIND

15. Winds are created by differences in air pressure due to unequal heating of air

17. Wind is air moving from HIGH PRESSURE areas to low pressure areas

18. H L

19. Why does air move from high pressure to low pressure?11

20. N2 O2 N2 N2 N2 O2
H2O N2 N2 N2

22. ●990 mb
●988 mb
●988 mb
●989 mb
●990 mb
●997 mb
●994 mb
●992 mb
●996 mb
●1000 mb
●994 mb
●1000 mb
●999 mb
●996 mb
●996 mb
●998 mb
●994 mb
●992 mb
●991 mb
●990 mb

23. ●989 mb
●995 mb
●988 mb
●996 mb
●994 mb
●992 mb
●991 mb
●998 mb
●996 mb
●996 mb
●1000 mb
●997 mb
●999 mb
●996 mb
●1001 mb
●999 mb
●1001 mb
●1001 mb
●1003 mb
●1000 mb

24. ●999 mb
●995 mb
●1002 mb
●996 mb
●994 mb
●997 mb
●1000 mb
●994 mb
●991 mb
●993 mb
●995 mb
●994 mb
●990 mb
●999 mb
●995 mb
●996 mb
●996 mb
●998 mb
●1001 mb
●1000 mb

25. ●1015 mb
●1005 mb
●1020 mb
●1000 mb
●1007 mb
●1014 mb
●1020 mb
●1001 mb
●1006 mb
●1011 mb
●1000 mb
●1013 mb
●1007 mb
●1019 mb
●1003 mb
●1015 mb
●1006 mb
●1010 mb
●1002 mb
●1018 mb

26. What direction is the wind blowing?
Where are the winds strongest?
Where are the winds weakest?
What is the weather like in Stoneham?
What will the weather be like in the near future?

27. What direction is the wind blowing?
Where are the winds strongest?
Where are the winds weakest?
What is the weather like in Stoneham?
What will the weather be like in the near future?

28. What direction is the wind blowing?
Where are the winds strongest?
Where are the winds weakest?
What is the weather like in Stoneham?
What will the weather be like in the near future?

29. What direction is the wind blowing?
Where are the winds strongest?
Where are the winds weakest?
What is the weather like in Stoneham?
What will the weather be like in the near future?

31. Great Lakes
Oregon
Mass
Colorado
Texas
Baja Cali
Florida

33. Local Winds

36. Global Winds

39. The Coriolis Effect

44. 9

45. L
1000
1015

46. H
1015
1000

48. Doldrums?

50. Why does it rain a lot at the equator?

54. Why is weather generally considered nice at 30 degrees?