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AIR PRESSURE

AIR PRESSURE. Chapter 18 Test 5 material Begin. AIR EXERTS A FORCE ON THE SURFACE OF OBJECTS THAT IT CONTACTS. AIR PRESSURE IS A MEASURE OF THAT FORCE PER UNIT OF SURFACE AREA. VARIATIONS WITH ALTITUDE.

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AIR PRESSURE

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  1. AIR PRESSURE Chapter 18 Test 5 material Begin

  2. AIR EXERTS A FORCE ON THE SURFACE OF OBJECTS THAT IT CONTACTS. • AIR PRESSURE IS A MEASURE OF THAT FORCE PER UNIT OF SURFACE AREA

  3. VARIATIONS WITH ALTITUDE • WITH FEWER AIR MOLECULES IN THE UPPER ATMOSPHERE, THE PRESSURE DECREASES AS WE RISE IN THE ATMOSPHERE • IT DECREASES AT AN INCREASING RATE

  4. MOUNTAIN AIR EFFECTS • MOUNTAIN SICKNESS • DIZZY • HEADACHE • SHORTNESS OF BREATH • RED BLOOD CELL COUNT NEEDS TO INCREASE • THINK CUBS WILL WIN IT ALL

  5. HORIZONTAL VARIATIONS • AIR PRESSURE DIFFERS FROM ONE PLACE TO ANOTHER AND THESE MIGHT NOT BE FROM ELEVATION DIFFERENCES ALONE

  6. AIR MASS • HUGE VOLUME OF AIR THAT IS RELATIVELY UNIFORM IN TEMPERATURE, DENSITY, AND WATER VAPOR CONTENT • AS AIR MASS MOVES ACROSS THE EARTH’S SURFACE THE PRESSURE FALLS OR RISES BASED UPON QUALITY OF THE AIR MASS

  7. AIR MASS CHANGES • RISING PRESSURE = IMPROVING WEATHER • FALLING PRESSURE = STORM Y WEATHER • STEADY PRESSURE = WEATHER STAYS THE SAME

  8. WHICH IS HEAVIER? • COLD OR WARM AIR? • DRY OR MOIST AIR?

  9. WHEN MOISTURE IS ADDED TO THE AIR, A HEAVIER GAS IS REPLACED BY THE WATER VAPOR SO MOIST AIR IS LIGHTER THAN DRY AIR

  10. HIGH PRESSURE • DIVERGENCE OF AIR • ANTICYCLONE

  11. LOW PRESSURE • CONVERGANCE OF AIR • CYCLONE

  12. PRESSURE UNITS • MILLIBARS = 1014 MB AT SEA LEVEL • INCHES = 29.92 INCHES AT SEA LEVEL

  13. PRESSURE MEASUREMENTS • BAROMETER - MERCURY OR ANEROID ( LEGENDS ON THE DIAL) • BAROGRAPH • ALTIMETER

  14. WIND • Chapter 18 • Test 5 Material

  15. FACTORS OR FORCES THAT INFLUENCE WIND • PRESSURE GRADIENTS • CORIOLIS EFFECT • FRICTION • CENTRIPETAL AND CENTRIFUGAL FORCE • GRAVITY

  16. A GRADIENT IS SIMPLY A CHANGE IN SOME PROPERTY WITH DISTANCE. PRESSURE GRADIENT IS DIFFERENCE IN AIR PRESSURE FROM ONE PLACE TO ANOTHER.

  17. A GRADIENT IS SIMPLY A CHANGE IN SOME PROPERTY WITH DISTANCE. PRESSURE GRADIENT IS DIFFERENCE IN AIR PRESSURE FROM ONE PLACE TO ANOTHER.

  18. AN ISOBAR IS A LINE THAT CONNECTS POINTS OF EQUAL AIR PRESSURE. • WHEN ISOBARS ARE CLOSELY SPACED, WE HAVE A STRONG PRESSURE GRADIENT AND HIGH WINDS. • WHEN THE ISOBARS ARE FAR APART, THE GRADIENT IS WEAK AND WINDS ARE LIGHT.

  19. EARTH’S ROTATION IS RESPONSIBLE FOR THE CORIOLIS EFFECT WHICH IS A DEFLECTION OF THE WINDS. • IN THE NORTHERN HEMISPHERE, WINDS ARE DEFLECTED TO THE RIGHT; • IN THE SOUTHERN HEMISPHERE TO THE LEFT.

  20. CENTRIPETAL FORCE • AN INWARD PULLING FORCE

  21. CENTRIFUGAL FORCE • AN OUTWARD PULLING FORCE

  22. CENTRIPETAL AND CENTRIFUGAL FORCE TOGETHER PRODUCE A CIRCULAR PATTERN OF WINDS AROUND HIGH AND LOW PRESSURE SYSTEMS

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