1. V. Air Pressure and motion
A. Air pressure is the weight of air at any particular point. It is also called barometric pressure.
The units are given in the ESRT in millibars and inches of mercury and as atmospheres.
A barometer is a tool used to measure pressure,
Air pressure depends on how tightly packed the molecules are and how heavy they are.
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2. B. Units of air pressure: page 13 ESRT
For normal, sea level pressures,
the air pressure will be found on
this chart.
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3. C. What’s a ‘rising barometer’?
When air is ‘heavy’ it pushes down (and around) on objects. The mercury will ‘rise’ in the vacuum tube.
So a rising barometer means clear weather.
When air is ‘light’, it does not push down as much and the mercury in the barometer will ‘fall’ in the vacuum tube.
So a falling barometer means poor weather.
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4. Heavy Air: (high pressure)
D. Remember……
Heavy Air: (high pressure)
cold, because the molecules are close together.
Dry, because nitrogen and oxygen are heavier than water vapor.
Light Air: (low pressure)
warm; the molecules have more_energy and are farther apart.
humid, because water vapor is a very light molecule.
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jason.org

5. E. The reason some air is light and some air is heavy is due to
the unequal heating of the atmosphere due to our round
rotating planet.
ffden-2.phys.uaf.edu
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6. Air moves from areas of high pressure to areas of low pressure.
VI. Why wind?
A. Air pressure and wind
Air moves from areas of high pressure to areas of low pressure.
Air flows from regions of heavy, sinking air to regions of light, rising air.
Descending air means clear skies. (clouds can’t form)
Ascending air happens at fronts and in very warm, wet air (afternoon thunderstorms)
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7. B. Isobars
Weather maps show pressure systems using isobars. (lines that connect points of equal air pressure)
The closer the isobars are on the map, the greater the change in pressure and the faster the wind is blowing, There is a rapid change in air pressure.(like popping a balloon)
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8. https://courseware. e-education. psu
allows students to practice making isobars. It will convert from station model pressure to millibars for them and draw the lines for them to check
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9. C. Comparing high pressure to low pressure
High pressure system air is dry, and is probably falling, creating convection. High pressure air blows outward and clockwise across the surface.
Low pressure system air is light and is probably rising, creating convection.
Air blows inward and counterclockwise and rises.
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10. VI. Jet stream and Coriolis move our weather
A. Meteorologists know that midlatitude weather tends to move from west to east in the continental U.S. because of the planetary winds.
B. The Coriolis effect helps move the air from the southwest toward the northeast (usually).
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11. C. The Jet Stream :discovered by WWII pilots flying cross country.
It is a high altitude wind that separates the polar air from the warmer tropical air in the midlatitudes.
The jet stream is caused by interactions in upper levels of the troposphere.
Most active during our winter season; cold, dry Canadian air meets warm, moist air of the Gulf of Mexico.
the jet helps determine the weather patterns for the country.
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12.
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13. What are 2 characteristics of heavy air? Of Light air?
Self-check:
What are 2 characteristics of heavy air? Of Light air?
What air is rising: heavy or light? High pressure or low pressure?
Why does wind blow?
Does it blow from high to low or low to high?
Can you draw wind around a high? Around a low?
Which way do storms move across the US?
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