1. The Atmosphere
Chapter 12

2. The Air around you
Section 1

3. Essential Questions What is the composition of Earth’s atmosphere?
How is the atmosphere important to living things?
What causes smog and acid rain?

4. Weather is the condition of Earth’s atmosphere at a particular time and place.
Earth’s atmosphere is a thin envelope of gases that surrounds the planet and protects it.
It is a thin layer of air forming a protective covering around the planet. (from Glencoe book)

5. Composition of the Atmosphere
Earth’s atmosphere is made up of nitrogen, oxygen, carbon dioxide, water vapor, and many other gases, as well as particles of liquids and solids.

6. What is the atmosphere made of?
It is made of gases, solids and liquids
Solids include dust, salt, and pollen
It is 78% nitrogen, 21% oxygen, and 1% other materials
It has 5 layers

7. Nitrogen The most common gas in the atmosphere
Makes up more than ¾ of the air we breathe
Each molecule consists of two nitrogen atoms
Moves in a cycle from the air to the soil, into living things, and back into the air

8. Oxygen Second most abundant gas in the atmosphere
Plants produce oxygen in a process called photosynthesis – they combine water, carbon dioxide, and light
Like nitrogen, oxygen moves through a cycle involving living things
Burning any fuel uses oxygen
Rust is created very slowly by steel reacting to oxygen

9. Ozone “supercharged oxygen”
Formed from oxygen with three oxygen atoms in each molecule instead of the usual two
The ozone layer helps protect Earth from ultraviolet radiation given off by the Sun

10. Carbon Dioxide Plants use carbon dioxide from the air to make food
Each molecule has one atom of carbon and two atoms of oxygen
Plants and animals give off carbon dioxide
Burning fuels (such as coal and gasoline) releases carbon dioxide into the atmosphere

11. Other Gases
Argon and carbon dioxide make up most of the 1% of the atmosphere that isn’t nitrogen or oxygen
Trace gases are the other gases in the atmosphere. There are only small amounts of these

12. Water Vapor Water in the form of a gas
It is invisible (steam is tiny droplets of water and is NOT water vapor)
Each water molecule contains two atoms of hydrogen and one atom of oxygen
Very important in weather
Clouds form when water vapor condenses to form tiny droplets of water in the air

13. Particles Solids and liquids – dust, smoke, salt, and other chemicals
Most are too small to see

14. Earth’s atmosphere as seen from space

15. What does the atmosphere do for us?
It traps oxygen close to Earth for us to breathe.
It helps keep the perfect temperature on Earth for plants and us to live. It traps energy from the Sun.
It protects the planet from harmful ultraviolet radiation from the Sun.
It protects us from space objects striking Earth (such as meteoroids – space rocks)
Because the atmosphere is constantly changing, the air can be considered a renewable resource

16. Asteroid grazing Earth’s atmosphere

17. What would life be like on Earth without the atmosphere?
During the day temperatures would rise very high and probably be too hot for life.
During the night temperatures would drop to very cold levels.

18. Air Quality
The air we breathe into our bodies may be filled with harmful chemicals and particles
Pollutants are harmful substances in the air, water, or soil
Air pollution can affect the health of humans and other living things

19. Sources of Pollution
Natural processes can add particles to the atmopshere
Forest fires, soil erosion, dust storms all add smoke and dust to the air
Wind carries molds and pollens
Erupting volcanoes spew out dust, ash, and poisonous gases
Burning fossil fuels adds carbon monoxide, nitrogen oxides, and sulfur oxides to the air

20. Smog & Acid Rain Caused by the burning of fossil fuels
Smog = smoke + fog; a type of air pollution
Photochemical smog – formed when sunlight acts upon hydrocarbons and nitrogen oxides. It is a brown haze in the sky.
Can be harmful to plants and can irritate humans

21. Acid Rain Rain that contains more acid than normal
Caused when water vapor mixes with harmful nitrogen oxides and sulfur oxides in the air
Can be strong enough to damage surfaces of buildings and statues
Harmful to lakes and ponds

22. Improving Air Quality
The US has many laws to protect and clean up the air
The Environmental Protection Agency (EPA) monitors air pollutants in the US
Air quality has improved because of improvements to automobiles and power plants
More cars and more power plants are needed now, so air quality still needs to improve

23. Solutions for Improving Air Quality
Use public transportation as much as possible
Stricter regulations might be needed
Could this cost too much?

24. Review Quiz The most abundant gas in the atmosphere is Ozone
Water vapor
Oxygen
Nitrogen

25. Quiz continued
___________ is the condition of Earth’s atmosphere at a particular time and place.
Climate
Temperature
Weather
Ozone

26. Quiz continued
True or False: Earth’s atmosphere makes conditions on Earth suitable for living things.
Smog and acid rain can be caused from burning
Coal
Petroleum oil
Natural gas
All of the above

27. Essential Questions Answered
What is the composition of Earth’s atmosphere?
78% nitrogen, 21% oxygen, 1% other
How is the atmosphere important to living things?
It holds oxygen, keeps Earth warm, and protects us from UV rays and meteors.
What causes smog and acid rain?
Pollution from burning fossil fuels