Pressure in Gases

• Physics
• Secondary Education
• Age 13

Forces and Motion

Lesson 08b. 

Pressure in Gases

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Highlights of the Day

• use the particle theory to explain pressure in gases and liquids (qualitatively only)

• Values :  Responsibility and Determination

Review Quiz

The pressure in the water increases with ___________.

1. depth
2. distance
3. gravity

The water at the bottom of a container has _________ pressure than the one near the top.

1. less
2. more
3. equal

The more molecules or particles a volume has, the ________ the pressure.

1. higher
2. lower
3. slower

The lower the temperature, the ________ the pressure.

1. higher
2. lower
3. slower

The larger the volume, the ________ the pressure.

1. higher
2. lower
3. slower

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Pressure and depth in gases

• As with liquids, the pressure in a gas increases with depth.
• Altitude is height above sea level.
• Most people on Earth live at low altitude.

The Earth’s _____________, which we call air, is made from gases. The atmosphere extends to a height of about above sea level.

1. hydrosphere
2. atmosphere
3. geosphere
4. biosphere

Sea level is where the atmosphere is at its "deepest". So, at sea level, atmospheric pressure is ___________.

1. highest
2. lowest
3. equal
4. zero

As you go higher in the atmosphere, the number of particles in of air ___________, so the concentration of gas particles decreases.

1. decreases
2. increases
3. remains constant
4. becomes zero

As you go _________ in the atmosphere, the weight of air above your current position decreases.

1. lower
2. higher
3. in the middle
4. closer

Atmospheric Pressure

• Atmospheric pressure at sea level is about 14.7 pounds per square inch. This pressure is the equivalent of the weight of two large elephants pushing on every of surface.

Effects of atmospheric pressure

• The effect of atmospheric pressure can be shown by pumping the air out of a metal container.

Summary

Self-survey: Rate your level of understanding and participation in this lesson.

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