New Area of Focus: Air Pressure, The factor that controls the weather. New Area of Focus: Air...

New Area of Focus: Air Pressure, The New Area of Focus: Air Pressure, The factor that controls the weather.factor that controls the weather.

Copyright © 2010 Ryan P. Murphy

• Class Demo: Does air have weight?– How could we measure the weight of air?


• Air is made of matter. Matter has mass and takes up space.


“Ouch!” “Air molecules are everywhere.”

• Activity / Demonstration: Balloon in a bottle.– Fit a balloon around the edges of a bottle and

push it inside. – Try and blow up the balloon. What happens?– Use a pin to poke a hole in the bottom and try

again.– Practice covering the hole and releasing.

• Activity / Demonstration: Balloon in a bottle.– Fit a balloon around the edges of a bottle and

push it inside. – Try and blow up the balloon. What happened?– Teacher to use a nail and hammer to poke a hole

in the bottom and try again. (Eye protection)– Practice blowing up the balloon and then

plugging with your finger when inflated.

Air Pressure: The pressure caused Air Pressure: The pressure caused by the weight of the atmosphere. by the weight of the atmosphere.


Air Pressure: The pressure caused by Air Pressure: The pressure caused by the weight of the atmosphere. the weight of the atmosphere.


Air pressure applies a force equal in Air pressure applies a force equal in all directions.all directions.


As elevation increases, air pressure As elevation increases, air pressure decreases.decreases.


• Mt. Everest – Death Zone past camp IV because there are very few air molecules.


• Mt. Everest – Death Zone past camp IV because there are very few air molecules.– Including oxygen


As you increase in elevationAs you increase in elevation


As you increase in elevation As you increase in elevation


Low Pressure

As you increase in elevation As you increase in elevation air air pressure decreases. pressure decreases.


Low Pressure

As you increase in elevation air As you increase in elevation air pressure decreases. pressure decreases. As you As you decrease in elevation decrease in elevation


Low Pressure

As you increase in elevation air As you increase in elevation air pressure decreases. As you pressure decreases. As you decrease in elevation decrease in elevation


Low Pressure

As you increase in elevation air As you increase in elevation air pressure decreases. As you pressure decreases. As you decrease in elevation decrease in elevation


Low Pressure

High Pressure

As you increase in elevation air As you increase in elevation air pressure decreases. As you pressure decreases. As you decrease in elevation decrease in elevation pressure pressure increases. increases.


Low Pressure

High Pressure

• As you increase in elevation…– air pressure decreases.

• As you increase in elevation…– Air pressure decreases.

Low Pressure

Low Pressure

Higher Pressure

• Water is heavy and can create enormous pressures as you go down in depth.

Barometer: Instrument that Barometer: Instrument that measures air pressure.measures air pressure.


• Standard sea-level pressure is 14.7 lb per sq in. (1,030 grams per sq cm), which is equivalent to a column of mercury 29.92 in. (760 mm) in height;

• The decrease with elevation is approximately 1 in. (2.5 cm) for every 900 ft (270 m) of ascent.


AA rising barometer = Increasing air pressure.rising barometer = Increasing air pressure.

This usually means…This usually means…


• High pressure = Good Weather


• Low Pressure = Poor weather coming

• Word Bank: Titanic wreck, Top of Mt. Everest, sea-level, jet plane, bottom of your pool, hot air balloon.

High Pressure Low Pressure


TitanicWreck




TitanicWreck

Top of Mt.

Everest




TitanicWreck

Top of Mt.

EverestSea-Level




TitanicWreck

Top of Mt.

EverestSea-Level

Jet Plane




TitanicWreck

Top of Mt.

EverestSea-LevelBottom

of a Pool

Jet Plane




TitanicWreck

Top of Mt.

EverestSea-LevelBottom

of a Pool

Jet PlaneHot Air Balloon

• Activity! Marshmallow torture

• Activity! Marshmallow torture– Place Marshmallow into Bell Jar vacuum.– Remove Air from Bell Jar– Record Picture of Marshmallow.– Quickly let air rush back in and observe.

New Area of Focus: Air Pressure, The factor that controls the weather. New Area of Focus: Air...

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