1. Earth’s Atmosphere
Chapter 1

2. The Atmosphere A whole layer of air that surrounds Earth
Supports and protects life
Keeps Earth warm
Very thin

3. The Atmosphere’s Altitude
The air becomes thinner as the altitude increases.
Altitude: distance above sea level
Altitudes above 500 km/300 mi is considered to be outer space

4. The Atmosphere’s Density
The thickness and thinness of air is measured by its density.
Density: the amount of mass in a given volume of a substance
D = M/V
Density decreases as altitude increase
The air at the top of a mountain is less dense than air at sea level.

5. What does this mean?
The decrease in density with the increase in altitude means that most of the atmosphere is close to Earth.
More than 99% of the atmosphere’s mass is in the lowest 30 km/20 mi.

6. What is the atmosphere made of?
Mostly made of gases.
Nitrogen (N) – 78%
Oxygen gas (O) – 21%
Argon, CO2, other gases – 1%
Some small liquid and solid particles
Dust, sea salt, water droplets

7. Atmospheric Gases
Nitrogen promotes plant growth and is in all living things.
Oxygen is needed for plants and animals to breathe.
CO2 is used to make food for plants.

8. The Changing Atmosphere
Different natural processes continuously change the atmosphere.
The Carbon Cycle
The Nitrogen Cycle
The Water Cycle

9. The Carbon Cycle
CO2 and O2 cycle among plants and animals in the atmosphere.
Animals inhale O2 and exhale CO2
Plants take in CO2 and release O2

10. The Nitrogen Cycle
Different forms of nitrogen cycle between plants, animals, and the soil.
Nitrogen gas (N2) is taken from the air and turned into other types of N.
Plants and animals use N for energy and then release it back into the soil.

11. The Water Cycle Different forms of H2O cycle through the atmosphere
What are the steps of the water cycle??

12. The Changing Atmosphere
In addition to natural cycles, there are sudden changes that happen in the atmosphere.
Volcanic Eruptions: shoot gases into atmosphere
Forest Fires: releases excess CO2
Dust Storms: adds excess solid particles to air

13. Atmospheric Temperature
Chapter 1, Section 2

14. Heat Transfer
Heat is transferred throughout the atmosphere in 3 main ways:
Radiation
Conduction
Convection

15. Sunlight in the Atmosphere
When sunlight hit the atmosphere, some of the light is reflected (bounced in a different direction), and some of the light is absorbed.
Light colors reflect, dark colors absorb
The absorbed energy heats the objects that it touches

16. Radiation Radiation is the transfer of energy through waves.
About 30% of sunlight is reflected by the Earth’s surface and clouds in the atmosphere
The other 70% is absorbed by the Earth’s surface and atmosphere.

17. Conduction
Conduction is the direct transfer of heat from one substance to another through touching.

18. Convection
Convection is the transfer of heat from one place to another through the motion of liquid or gas.
Differences in the air’s density causes convection.
Warm air rises into the atmosphere, and eventually will cool enough to sink back down.

19. The Layers of the Atmosphere
The transfer of heat energy changes in the different layers of the atmosphere.
Troposphere
Stratosphere
Mesosphere
Thermosphere

20. Troposphere The layer nearest Earth’s surface
Contains about 80% of the mass in the atmosphere and almost all of the water vapor
Warmest at ground level and goes down about 6.5 degrees C every kilometer.

21. Stratosphere A clear, dry layer
Contains gas we call ozone. This absorbs a type of solar radiation that is harmful to life.
The radiation raises the temp of the air, and the temp rises the higher you go into the stratosphere.

22. Mesosphere The air is extremely thin here.
Contains less than 0.1% of the atmosphere’s mass.
Meteors burn in this layer.
The air here is heated from below, so the further you rise, the cooler it gets.

23. Greenhouse Gases & Pollution
Chapter 1, Sections 3-4

24. Atmospheric Gases The atmosphere can affect light in four ways:
Absorb light
Reflect light
Let light pass through it
Give off light/radiation

25. Thermosphere Starts about 90 km/56 mi above Earth’s surface
It gets less dense as altitude increases, but the temperature goes up.
The air high in this layer (closest to outer space) gets very hot from solar radiation
The air here is heated from below, so the further you rise, the cooler it gets.

26. Radiation Ultraviolet (UV) radiation: Infrared (IR) radiation:
Travels in waves
Have more energy than visible light
Can cause sunburn, skin cancer, and sight problems
Harm crops and other materials
Infrared (IR) radiation:
Has less energy than visible light
Warms the materials that absorbs it

27. Ozone Layer Ozone (O3) is made of three oxygen atoms.
The ozone layer protects life on Earth because it absorbs UV radiation, but lets other gases pass through.
Some chemicals can destroy ozone, such as chlorine.
To protect the ozone layer, more than 180 nations have signed the Montreal Protocol
This states that they will stop using/producing chemicals that could be harmful to the ozone layer.

28. Greenhouse Gases
Certain gases “trap” heat inside Earth’s atmosphere to keep the energy (heat) here longer.
Carbon dioxide, methane, water vapor, nitrous oxide, etc.
Most are kept in the troposphere
This is known as the “Greenhouse Effect”
Without this, heat would escape the atmosphere and Earth’s temperature would be about 0 degrees F.

29. Greenhouse Gases
G.G.s have helped support plant and animal life by maintaining a suitable temp on Earth.
Human practices have been producing excess G.G.s too quickly for them to naturally be removed from the atmosphere.
CO2 goes up 0.4% each year
With an increase in G.G.s, comes an increase in temps
Global Warming

30. Global Warming Can affect resources such as food and water.
Scientists predict the average temp to change between degrees F by the year 2100.

31. Reducing G.G.s
This is a global issue, so all countries would have to be in agreement to reduce the release of gases into the atmosphere.
The Kyoto Protocol
In 1990, the US released more than 1/3 of the world’s greenhouse gases. We have not accepted the agreement to reduce our gas release.

32. Air Pollution
Smoke and other harmful materials are called air pollution.
Gas pollutants
CO, methane, O3, sulfur oxides, and nitrogen oxides.
Only a pollutant if they can cause harm.
Particle pollutants (particulates)
Dust, dirt, pollen, sea salt

33. Causes of Pollution Burning of fossil fuels such as oil, gas, and coal
Fossil fuels are the remains of prehistorical animals and plants
Smog
Combo of smoke and fog
Sunlight causes fumes from gasoline to react chemically, creating a haze

34. Effects of Pollution Health issues Particulates can:
Irritate your eyes, nose, throat, and lung
Particulates can:
Stick to surfaces and damage living organisms
Dust can make it hard to see

35. Controlling Pollution
National, state, and local governments can make laws, create agreements, etc… to control pollution
The Clean Air Act limits the amount of pollution that factories can release
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