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Lesson on Atmospheric Pressure
In this lesson we are going to learn about the definition of atmospheric pressure, the instruments used in measuring it and how they work

Answer Text:
Atmospheric Pressure
-The force exerted by gases in the atmosphere on some area or body on the earth’s surface.
-Measured using barometers of three types namely mercury, aneroid and Fortin Barometers.
Mercury Barometer

How It Works
• Air exerts pressure on the mercury in the beaker.
• The height of mercury in the tube is proportional to the atmospheric pressure.
• The readings are taken in mmHg.
• Its 760mmHg at sea level
Advantage
Quite accurate
Disadvantage
1. Cumbersome to carry around.
2. Can be damaged quite easily while being carried around.
Aneroid Barometer
-Measures changes in atmospheric pressure.
How It Works
• Has air tight compartment (vacuum).
• Compartment expands when pressure decreases.
• It collapses when pressure increases.
• The movement is transmitted by lever to a pointer on a dial.
• The readings are in kg/cm3.