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Published byAgnes Andreassen Modified over 6 years ago
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AIR PRESSURE Air has pressure because gravity pulls air down on us.
Air’s Pressure = Air’s Density = Air’s Weight If air density changes then air pressure changes.
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The atmosphere is high and heavy.
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Prove it with a straw
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How do you drink through a straw?
Air Pressure How do you drink through a straw?
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The atmosphere is so heavy it can push water up about 30 feet!
Air Pressure The atmosphere is so heavy it can push water up about 30 feet!
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1 atmosphere is about a ton of weight on the average human.
About the weight of a Honda Civic!
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Since gravity pulls air down, the higher you go the less air.
Less dense, less weight, less pressure. Less Pressure! More Pressure!
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Water Air Pressure Is using a 30 foot water tube a practical method to weigh the atmosphere?
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Mercury is more dense than water and only rises 3 ft (1 m).
Add a scale, and a Mercury Barometer measures air pressure. (It weighs air!)
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Barometers measure air’s pressure very accurately.
Mercury Barometers measure air’s pressure very accurately. BUT, mercury is poison!
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ANEROID BAROMETER
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ANEROID BAROMETER
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A barometric pressure of 1021
A barometric pressure of millibars is equal to how many inches of mercury? (1) (3) 30.25 (2) (4) 30.50
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