1. Earth’s Changing Atmosphere
Chapter 15
Part 1 Life Support System

2. 15.1 Earth’s Atmosphere Supports
Life
• Vocabulary—
– Atmosphere – the layer of air that surrounds Earth
– Altitude – distance above sea level
– Density– the amount of mass in a given volume
– Cycle– a process that repeats over and over
• 1) Matter comes in three states.
(Actually 4– don’t forget plasma!) Sketch
an example of each.

3. States of matter

4. And don’t forget PLASMA!!!

5. How they change “states”
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6. The Atmosphere Makes Life on
Earth Possible
• 2) Write two ways that the atmosphere
makes life possible on Earth.
– Keeps Earth’s temperature even
– Transports energy
– Protects from excessive solar radiation
• 3) Characteristics of the Atmosphere
– Draw a picture of a mountain. Mark an X
where the atmosphere’s density is greatest.

7. Earth’s Atmosphere
That thin blue haze is
the atmosphere

8. Materials in the Atmosphere
• 4 Label the two most common gasses in the atmosphere
and write the percentage of each.
Oxygen
21%
Nitrogen
78%

9. Natural Processes Modify the
Atmosphere
• 6) What is a cycle?
– A Cycle is a process that repeats over and
over.
• 7) Look at the cycles shown in your
textbook. How are all of the cycles alike?
– Materials leave the air and return to the air
over and over again.

10. t

11. More Ongoing Processes
• 8) Fill in the chart to show three events that change the
atmosphere suddenly. Name the event and the
materials that get added to the atmosphere.
Sudden changes
affect atmosphere
1. Volcanic eruptions: gasses and ash
2. Forest Fires: carbon dioxide, ash
3. Dust storms: soil, microbes

12. Other sources of
greenhouse
gases
• Volcanoes
• Forest Fires
• Dust Storms

13. Effects of Volcano on Atmosphere

14. Volcanic Activity
• Mt. Pinatubo, 1991
That thin dark grey line
is the layer of Pinatubo
ash in the stratosphere.
It affected weather on
Earth for over 2 years
until it settled out onto
the surface.
Layer of Pinatubo ash

15. Effects Worldwide
• Each dip in temperature
reflects the effect of a
large volcanic ash
eruption on worldwide
temperatures
As you can
see, the
temperature
takes a couple
years to return
to normal after
each eruption.

16. Fire Effects
Satellite images of
fires in Amazon

17. Dust Storms
Affect all major cities in
or near desert settings,
even in Phoenix, AZ!
Dust from
the Sahara
can travel
and be found
5000 miles
away in the
Caribbean!

18. Dust Storms
During the 1930’s
in Midwest
In Melbourne, Australia, one of
Australia’s largest cities.
The dust gets through ANY
household opening. There is 0
visibility in one.

19. 15.2 The Sun Supplies the
Atmosphere’s Energy
• Vocabulary
– Radiation = energy that moves across
distances in the form of certain types of
waves
– Conduction = the moving of heat energy by
one substance touching another
– Convection = the moving of heat energy by
the motion of a gas or liquid
• 1) What are the two most plentiful gasses in
Earth’s atmoshpere?
– Nitrogen and oxygen

20. Energy from the Sun heats the
atmosphere
• 2) The circle graph shows the average amounts of solar
radiation that are absorbed and reflected on Earth.
Complete the graph by labeling its parts.

21. The specifics

22. Atmosphere moves energy
• 3) List 3 ways that energy is moved from
place to place.
– Radiation, conduction, convection

23. Radiation
• 4) Earth’s surface
becomes warmer when it
is heated by radiation
from the sun.

25. Conduction
• 5) Explain why the bowl of the metal
spoon gets hot after resting in a mug of
very hot cocoa.
– Energy is conducted from the hot liquid to the
bowl of the metal spoon.

26. Convection
• 6) Complete the diagram to show how
convection works.
Radiation from
Sun heats ground Convection- the circulating
motion of hot and cold.
Warm ground heats
up air and air
becomes less dense Cool dense
air sinks
Less dense,
warm air rises
Conduction occurs where
Ground air “touches” ground

27. Convection at work
Hot material
rises
Cold material
sinks

28. The atmosphere has temperature layers.
• Label the following 2 lowest layers of the
atmosphere.
1) Stratosphere •Contains ozone
•Temperature rises as move
upward
2) Troposphere •Contains almost all H2O vapor in
atmosphere
•Contains most mass of atmosphere
•Heated by ground, temperature falls as
move upward

29. Layers of Atmosphere

30. Particles blocked by
atmosphere

31. Atmosphere’s Temperature
Layers
• 8) Sometimes the tar of a newly paved
road gets sticky on a very hot summer
day. What causes this?
– Dark road absorbs solar radiation enough so
it heats up and starts to melt tar.

32. 15.3 Gases in the Atmosphere
Absorb Radiation
• Vocabulary
– Ultraviolet radiation – waves that have more energy than
visible light
– Infrared radiation – waves that have less energy than visible
light
– Ozone– a molecule containing three atoms of oxygen
– Greenhouse effect – the process by which gases absorb and
give off infrared radiation, which keeps energy in Earth’s system
for a while
– Greenhouse gases – water vapor, carbon dioxide, methane,
nitrous oxide, and other gases that absorb and give off infrared
radiation
• 1) What happens to solar radiation that reaches
Earth? Some is reflected back into space while
some is absorbed by Earth’s air, water, and
land.

34. Gases can absorb and give off
radiation
• 2) List four ways that gases in the
atmosphere can affect radiation.
– Absorb radiation
– Reflect radiation
– Let it pass through
– Emit radiation

35. Gases Can Absorb and Give Off
Radiation (continued)
• 3) Put descriptions of ultraviolet radiation and
infrared radiation into the frame game diagram.
• Ultraviolet radiation – like sound too high to
hear, ozone absorbs it, shorter wavelength, has
more energy than visible light
• Infrared radiation– like sound too low to hear,
longer wavelength, has less energy than visible
light, greenhouse gases absorb and reflect this

36. Behavior of Ultra-Violet
Radiation

37. Behavior of Infrared Radiation

38. The Ozone Layer Protects Life from
Harmful Radiation
• Draw a picture to show the difference
between a molecule of oxygen gas and a
molecule of ozone.
Ozone-
O2 reflects UV
Oxygen gas
(breathable)
O rays, but not
3 breathable

39. Ozone Layer
• 5) List 3 ways that the ozone protects life
on Earth.
– Reduces sunburn and skin cancer
– Reduces damage to eyesight
– Prevents crop damage

40. Ozone

41. The Greenhouse Effect Keeps
Earth Warm
• 6) Fill in the chart with facts about the ozone
layer and greenhouse effect.
Layer Gas(es) Type of
radiation
absorbed
Ozone stratosphere ozone (O3) Ultraviolet
layer
Greenhous Troposphere Greenhouse Infrared radiation
e effect gases (CO2 and
CO)

42. Greenhouse Effect

43. The Greenhouse Effect (continued)
• 7) What would happen on Earth if the
atmosphere didn’t have greenhouse
gases?
– Infrared radiation would bounce off Earth’s
surface into space leaving Earth’s average
temperature at -18°C which is too cold for life
dependant on liquid water.

46. 15.4 Human Activities Affect the
Atmosphere
• Vocabulary
– Air pollution – harmful materials that are added to the
air
– Particulate – any tiny particle or droplet of harmful
material that is mixed in with air
– Fossil fuel – fuel formed from the remains of once-living
plants and animals
– Smog – a combination of fog and smoke, or ozone and
other pollutants produced by sunlight and gases
• 1) What effect do greenhouse gases have on
Earth?
– Greenhouse gases absorb and emit infrared radiation that

47. Human activity can cause air
pollution
• 2) Suppose a factory in your town
released harmful substances into the air.
Is the effect of this air pollution limited to
your town? Explain why or why not…
– No! Air is fluid and will carry the pollution to
other towns.

48. Types of Pollution
• Gas Pollutants
– CO
– Methane
– Ozone
– Sulfur oxide
• Particle Pollutants
– Dust
– Dirt
– Pollen
– Salt

49. Pollutants
• 5) In cities, most air pollution comes from
the burning of fossil fuels. Smoke from
this burning can combine with water vapor
in the air or fog to produce smog.

50. Effects of Pollution
• 6) How does polluted air affect our health?
– Examples: Irritates eyes, nose, throat and
lungs. Causes allergies and breathing
problems.

51. Controlling Pollution
• 7) What are some things governments do
to control pollution and its effects?
– Smog and ozone laws to limit pollutants, laws
to increase fuel efficiency.

52. Human activities are increasing
greenhouse gases.
• 8) List three activities that can produce
greenhouse gases.
– CO2= burning of fossil fuels in cars, factories
and power plants
– Methane= cattle and livestock, landfills, and
bacteria in rice fields
– NO2= fertilizers and chemical factories

53. Global Warming
• 9) What do you expect to happen if
greenhouse gases such as carbon dioxide
keep increasing?
– Global temperatures will continue to rise.
This can affect sources of food, water, and
other resources available.

54. Reduction of Greenhouse
Gases
• 10) List three benefits of reducing the
amount of energy needed to heat
buildings, transport people, and make
products.
– saves resources
– Saves money
– Reduces greenhouse gases and other
pollutants

55. Human activities produce
chemicals that destroy the ozone
layer
• 11) What happens when a chlorine atom
enters the stratosphere? Why is this a
bad thing?
– It “steals” or takes an oxygen atom from
ozone molecules and thus depletes the ozone
layer. (With only 2 oxygen atoms, the
molecule no longer protects us from ultraviolet
radiation.)