Air Pressure. Elbow Chat What is weather? Describe the weather today.
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Transcript of Air Pressure. Elbow Chat What is weather? Describe the weather today.
![Page 1: Air Pressure. Elbow Chat What is weather? Describe the weather today.](https://reader036.fdocuments.us/reader036/viewer/2022082422/5697bfb71a28abf838c9eae9/html5/thumbnails/1.jpg)
Air Pressure
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Elbow Chat
• What is weather?
• Describe the weather today.
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• Weather: condition of Earth’s atmosphere at a particular time and place.
• It can change day to day.
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Elbow Chat
• Does air have mass?
• If so, how do you know?
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• Air has mass, which means it has “pressure”.
• Pressure: force pushing on an area
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Elbow Chat
• The weight of the column of air above your desk is about the same as the weight of an
entire school bus!
• Why does it not crush us?
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• Air molecules push in all directions, not just down on us. So the pressure evens out.
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• Barometer: tool used to measure air pressure
• AP drops – stormy
• AP rises – clear
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PROPERTIES OF AIR
• Air has mass.
• Density: the amount of mass in a given volume (space)
• Formula: D = M/V
• If there are more molecules in a given volume of air, the density is higher. If there are fewer molecules, the density is lower.
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AIR PRESSUREPressure: Force pushing on an area or surface
• Denser air exerts more pressure than less dense air.
• Air pressure:
• Definition: result of a weight of air pushing down
• Why does air pressure not crush us?
It is pushing in ALL directions, so it evens out.
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MEASURING AIR PRESSURE
• Falling air pressure means stormy weather is coming.
• Rising air pressure means fair/good weather is coming
• Barometer is the tool used to measure CHANGE in air pressure.
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INCREASING ALTITUDE• Altitude
Definition: distance above sea level
As altitude increases, air pressure and density decreases.
Air pressure is greatest at sea level.
Air at the top of the atmosphere has lower air pressure.
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Altitude affects density
*As you go up through the atmosphere, air pressure decreases.
As air pressure decreases, the density of air decreases.
• Why is it harder to breath at higher altitudes?
Air is less dense because the air is spread out. This means fewer oxygen molecules to breath in.