Atmospheric Pressure and Winds Flashcards
True or false: air is a physical substance.
True
What is air?
A mixture of several gases present in the atmosphere
Air has its own…
Weight
Air exerts _________ on the earth’s surface.
Pressure
The weight of the air on a unit area of the earth is called?
Air pressure
What is atmospheric pressure?
The force per unit area exerted against a surface by the weight of the air above that surface
Pressure is expressed in…
millibars (mb)
Pressure is measured using…
A mercury barometer
Average atmospheric pressure at sea level
1013.25 mb or 760 mm height of the column of mercury in a barometer at sea level
What happens to atmospheric pressure as height increases?
Decreases
How are winds formed?
Contrast in temperature cause changes in air density, which are responsible for variations in pressure. These variations cause horizontal movement of air called winds.
Atmospheric pressure is an important factor in?
Producing changes in weather
What do winds do?
Transport heat and moisture from one region to another and that helps in the occurrence of precipitation and effect both temperature and humidity.
What are isobars used for?
Variations in pressure are shown on maps by means of isobars
What are isobars?
Lines joining the places having the same barometric pressure
