1. ATMOSPHERIC PRESSURE http://www.youtube.com/watch?v= zl657tCCudw

2. Atmospheric Pressure Force or weight of air pushing down on any given area

3. Pressure Top of atmosphere Sea Level More Molecules High Pressure Less Molecules Low Pressure

4. Measuring Pressure Instrument -Barometer Mercury Aneroid

5. Units – Standard Sea Level Pressure: 29.92 inches of Hg or 1013.2 mb Isobars – lines of equal pressure on a weather map Millibars (mb) or Inches of Hg (mercury) ESRT Page 13

7. 13 ESRT Page

8. 30.10 inches of Hg = ______ mb 1019.3

9. A. Pressure Relationships Temperature Top of atmosphere Sea level COLD HOT Molecules slow down Weigh more High density Molecules move fast and far apart Weigh less Less density HIGH PRESSURE LOW PRESSURE

10. Moisture Increasing water vapor makes air Nitrogen weighs more than the water vapor that replaces it Therefore, moist air is lower pressure than dry air lighter

11. Altitude/Elevation Top of Atmosphere Sea Level HIGH PRESSURE LOW PRESSURE More molecules Less molecules

14. Therefore……. Air with most pressure is ____________ Air with least pressure is ___________ Cold and dry Warm and moist

15. In Graph Form Pressure vs. Temperature What kind of relationship? Indirect LowHigh Low High Pressure Temperature

16. In Graph Form Pressure vs. Moisture What kind of relationship? Indirect LowHigh Low High Pressure Moisture

17. In Graph Form Pressure vs. Elevation What kind of relationship? Indirect LowHigh Low High Pressure Elevation

18. Go to page 36 1. 996.0 mb = 29.41 inches of Hg 2. 1000 mb = 29.53 inches of Hg 3. 989.0 mb = 29.21 inches of Hg 4. 29.50 inches of Hg = 999.0 mb 5. 30.16 inches of Hg = 1021.3 mb 6. 28.82 inches of Hg = 976.0 mb