AIDE Earth Science Key Points

Chapter 9 "The Earth's Atmosphere"

 

Lesson 1 "Gases in the Atmosphere"

 

Key Vocabulary Terms

• atmosphere -layer of gases that surrounds the earth

 

Key Concepts

• The two main gases in the atmosphere are nitrogen and oxygen.
• The path oxygen and carbon dioxide take through the environment is a cycle. Plants give off oxygen. Animals and people take in the oxygen and lease carbon dioxide, which plants take in to make sugar and oxygen.
• Plants are the source of oxygen in the oxygen-carbon dioxide cycle.
• Bacteria are needed in the soil to change nitrogen into a form plants can use.
• Nitrogen is released back into the atmosphere when bacteria in the soil break down animal wastes and dead plants and animals, releasing nitrogen into the air.

 

Did you learn these Objectives?

• Can you identify the gases in the atmosphere?
• Are you able to describe the oxygen-carbon dioxide cycle?
• Are you able to describe the nitrogen cycle?

 

Lesson 2 "Layers of the Atmosphere"

 

Key Vocabulary Terms

• troposphere - bottom layer of the atmosphere, extending from ground level up to about 16 kilometers above the earth.
• stratosphere - second layer of the atmosphere; includes the ozone layer
• mesosphere - third layer of the atmosphere; the coldest layer.
• thermosphere - outermost layer of the atmosphere; includes most of the ionosphere
• ionosphere - layer of the atmosphere containing ions, or electrically charged particles.

 

Key Concepts

• The troposphere extends from the earth's surface to about 16 kilometers above it; air particles are packed most tightly in this layer; it contains 75 percent of the air particles in the entire atmosphere; most weather activity occurs in this layer.
• The stratosphere extends from 16 to 50 kilometers above the earth's surface; it is clear and dry; the ozone layer is in the lower half.
• The mesosphere extends from about 50-80 kilometers above the earth; it is the coldest layer.
• The thermosphere extends from about 80-480 kilometers above the earth; the air is thinnest here; the temperature in this layer increases with altitude, reaching 2,000 degrees Celsius; most of the ionosphere is in the thermosphere.
• We breathe the troposphere.
• The ozone layer is near the bottom of the stratosphere.
• In the ionosphere, the sun's energy strips electrons from atoms, making them ions, that is why it is called the ionosphere.
• AM radio waves bounce off the ions in the ionosphere and travel back to the earth. That is why AM waves travel further than FM.

 

Did you learn these Objectives?

• Are you able to identify the four layers of the atmosphere?
• Can you name one characteristic of each layer?

 

Lesson 3 "Clouds"

Key Vocabulary Terms

• evaporate - change from a liquid to a gas.
• water vapor - water in the form of a gas.
• condense - change from a gas to a liquid.
• altitude - height above the earth's surface
• stratus cloud - low, flat cloud that forms in layers.
• fog - stratus cloud that forms near the ground
• cumulus cloud - puffy, white cloud occurring at medium altitudes.
• cirrus cloud - high, wispy cloud made of ice crystals.

 

Key Concepts

• A cloud is a mass of water droplets in the air.
• The two most common ways for clouds to form is: (1) the sun's heat causes some of the water on the earth's surface to evaporate, and it becomes part of tech air. when the air is heated, it rises and takes water vapor with it. It cools as it rises, and the water vapor turns back into liquid. these are tiny droplets that stay afloat as a cloud. (2) When air is forced up a mountain, it cools. The water vapor in this air condenses to form clouds.
• At night the ground and the air above it cool quickly. If the water vapor in this air condenses, fog forms.
• Cumulus clouds are puffy and white, at altitudes from 200 to 7000 meters. Cirrus clouds are thin and wispy, at altitudes from 7000 to 13,000 meters.
• Stratus clouds are low, flat clouds in layers at altitudes less than 2000 meters.

 

Did you learn these Objectives?

• Can you explain how clouds form?
• Are you able to identify three kinds of clouds?

 

Investigation 9-1 "Observing Clouds." (Optional, must complete 16 total investigations)

Key Concepts

• You will observe and classify clouds over a period of several days.

 

Lesson 4 "Precipitation"

Key Vocabulary Terms

• precipitation - moisture that falls to the earth from the atmosphere.

 

Key Concepts

• Precipitation forms when water droplets in clouds combine into bigger droplets until they become heavy enough to fall.
• Four kinds of precipitation are rain, snow, sleet, and hail.
• Near the equator, the sunlight is most direct, so temperatures within most stratus clouds are above freezing. These clouds are mad entirely of water droplets and not ice crystals.
• Snow forms when the air temperature is below freezing beneath a cloud made of ice crystals. Sleet forms when rain falls through a layer of cold air and freezes into ice particles.
• Hail forms when strong winds cause ice crystals to move up and down inside a thunderstorm cloud. Layers of water gather and freeze around the crystals, developing hailstones.

 

Did you learn these Objectives?

• Can you describe how precipitation forms.
• Are you able to describe four kinds of precipitation.

 

Investigation 9-2"Making a Model of Rain" (Optional, must complete 16 total investigations)

Key Concepts

• You will make a model of water droplets and observe how they combine.

 

Lesson 5 "Wind Patterns"

 

Key Vocabulary Terms

• wind cell - continuous cycle of rising warm air and falling cold air.
• wind belt - pattern of wind movement around the earth.
• Trade wind - strong, reliable wind just north or south of the equator; blows from the east.
• prevailing westerly - wind generally between 30 degrees North and 60 degrees North latitudes, blows from the west.
• polar easterly -wind near a pole; blows from the east.

 

Key Concepts

• Air moves because unequal heating of the earth's surface by the sun.
• A wind cell is a continuous cycle of rising warm air and falling cold air.
• the earth's warmest air is near the equator.
• Trade winds are found just north and south of the equator; they low from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere.
• Most of the United States and southern Canada are in a prevailing westerly wind belt, which carries weather from west to east.

 

Did you learn these Objectives?

• Can you explain what causes air to move.
• Are you able to recognize how air moves in wind cells.
• Can you identify three wind belts?

 

Chapter Summary and Review

See page 226-227.

Chapter 9 Review answers are

1. trade winds

2. altitude

3. precipitation

4. condenses

5. evaporates

6. water vapor

7. polar easer lies

8. wind belt

9. stratus clouds

10. cirrus clouds

11. A thermosphere, B mesosphere, C stratosphere, D troposphere

12. A

13. D

14. B

15. C

16. C

17. D

18. A

19. Plants take in carbon dioxide and release oxygen. A decrease in plant life results in more carbon dioxide and less oxygen in the air.

20. The right side of the mountain may experience rain as the wind pushes the clouds higher, causing vapor to condense. The left side of the mountain may remain dry, since the water in the clouds already fell to the ground on the journey up the mountain.