Chapter 19Atmospheric Pressure
• Air Pressure
• High Pressure
• Low Pressure
• The weight of the atmosphere
• Good weather
• Bad weather
• Barometer • Instrument used to measure atmospheric pressure
• Either in mmHg or in millibars
• Dry Air……..
• Humid Air……….
• Heavy
• Lighter because the water molecules push the nitrogen and oxygen apart
• Isobar • Lines that connect points of equal PRESSURE
• Low pressure area
• High pressure area
• Air moves counterclockwise and in toward the low
• Air moves clockwise and out away from the High pressure area
• WIND!!!!! • The movement of air from an area of high to low pressure
• Coriolis Effect • Because the earth rotates to the East, winds on earth get deflected or turned to the west
Jet Stream
Land & Sea Breezes
• Warm breeze at night and a cool breeze during the day due to …..
• …the unequal heating of land and water
• Anemometer
• Wind Vane
• Measures wind speed
• Measures the DIRECTION of the wind
Chapter 21
• Climate is the long-term weather of an area• Weather changes day to day; climate
changes once every couple of centuries.• Virginia’s Climate is MILD.