Lecture 3: Earth’s Modern Atmosphere
Atmosphere: The thin veil of gases surrounding Earth, which forms a protective boundary between outer space and the biosphere. It extends about _______________ from the Earth’s surface. Above 300 miles
is the exosphere:
Air pressure averages nearly ___________ pounds per square inch at sea level. Air is denser (pressure
is higher) at the surface than it is higher up.
Why aren’t we crushed by air pressure?
Atmospheric pressure is measured in _____________________.
Which are FALSE?
A. Air pressure is defined as: the weight of the atmosphere.
B. We are not crushed by air pressure because of a counterbalancing force within us, pressing out. C. Gravity compresses air, so air is denser at the surface than it is higher up. D. The air pressure is nearly 200 pounds per square inch at sea level. E. Atmospheric pressure is measured in millibars here in the U.S.
F. Above 300 miles is the exosphere; below that is the earth’s atmosphere
G. The higher up, the more molecules there are in the air, and more oxygen you get with each breath.
Falling through Space
In 1961, Kittinger went up 19.5 miles and jumped out of a helium filled balloon. Why was the sky black?
Why didn’t he hear anything?
Why didn’t his air suit flutter in the wind?
Which is FALSE about Kittinger’s jump from space?
A. Although it was daytime, the sky was almost black, because there were no air molecules to
reflect the light.
B. There was a huge rushing noise as he hurtled through space.
C. His air suit didn’t flutter, because there wasn’t enough air to create friction
Composition of the Atmosphere:
Which answer contains three of the most important elements/molecules in the atmosphere?
A. Nitrogen, oxygen, helium
B. Oxygen, carbon dioxide, chlorine
C. Nitrogen, oxygen, carbon dioxide
D. Oxygen, carbon dioxide, helium
T/F Nitrogen accounts for roughly 65% of the atmosphere
T/F Oxygen accounts for roughly 45% of the atmosphere
T/F Carbon dioxide accounts for roughly 10% of the atmosphere.
Oxygen is a by-product of:_________________. Plants take in __________ carbon dioxide (CO) and emit _________. So in the very early history of the earth, since there were no plants, there 2
was no ______________ in the air.
Carbon dioxide: Although a very small proportion in the atmosphere, it plays a large role.
This is the famous ________________. Note that carbon dioxide levels move up and
down every year, but overall levels are rising.
What’s with carbon?
____________ forms the backbone of life on Earth. Complex molecules are made up of carbon bonded with other elements, especially oxygen, hydrogen, and nitrogen.
The Carbon Cycle
Plants ________ carbon. Animals take in the carbon through
plants (and other animals that ate plants).
When the plants and animals _________(or breathe), carbon is
_______ in the earth or _________ back into the atmosphere.
Carbon is also stored in the _________, in the water, plants, and
Formation of fossil fuels.
Fossil fuels were formed from dead plants and animals. Plants
and animals died and were covered by sediment in seas or swamps. This stopped them decaying. Further layers of sediment buried the plant and animal remains deeper and deeper. After millions of years of pressure and heat from being buried, these carbon remains turned into: Coal comes mainly from ___________, like trees, falling into swamps.
Oil and gas were formed from both plants and animals being buried.
Fossil fuels are made from ______________. Hence the name. When we burn fossil fuels we’re using
the ____________ that has been stored underground for millions of years. So, fossil fuels take millions of years to form, but only a moment to burn.
T/F In photosynthesis, plants take in oxygen and emit carbon dioxide.
T/F In the very early history of the earth, there was no oxygen in the air.
T/F The famous graph that shows carbon dioxide levels slowly rising, but with a distinct up and down annual cycle is known as the Namath Trend.
T/F The Keeling curve shows that carbon dioxide levels vary seasonally.
T/F The Browning curve shows that carbon dioxide levels are rising steadily.
T/F Nitrogen forms the backbone of life on Earth.
T/F Plants take in carbon when photosynthesizing.
T/F Animals take in the carbon through plants.
T/F When the plants and animals decay (or breathe), carbon is stored in the earth or released back into the atmosphere.
T/F Fossil fuels were formed from mud.
T/F The creation of fossil fuels begins when animals are covered by sediments, greatly speeding up their
T/F After roughly 10 years of being buried by light sediments, carbon remains turned into coal, oil and natural gas.
T/F Natural gas is mainly nitrogen formed at the beginning of the earth’s history.
T/F Coal is basically an igneous rock.
T/F Fossil fuels are fossiliferous, meaning made from rock.
T/F When we burn fossil fuels we’re using the sun’s energy that has been stored underground for millions of years.
A big transformation:
A gallon of gasoline turns into 19 pounds of carbon dioxide. If a gallon of gasoline weighs about six pounds, how can it produce three times that much greenhouse gas? Here’s how: The ________ from
the gasoline mixes with _______ from the air. Gasoline consists mostly of hydrocarbons—carbon
When the hydrocarbons burn, they break apart and recombine with the air. This reaction produces water and carbon dioxide.
A molecule of octane (gasoline) consists of ________atoms of carbon and 18 atoms of hydrogen.
If you break down the octane and mix it with enough oxygen from the air, you make ________________________ and nine molecules of water.
The eight molecules of carbon dioxide weigh about ____________ more than the one molecule of
octane you started with.
You've added the weight of the oxygen from the air to the weight of the carbon from the gasoline
T/F A gallon of fuel turns into roughly 1/2 pound of carbon dioxide
T/F Gasoline consists mostly of hydrocarbons.
T/F If you break down a molecule octane (gasoline) and mix it with oxygen from the air, you end up with two molecules of carbon dioxide.
US cars fuel use in one day:
• 5 million barrels at ________ each…
• 200,000,000 gallons total = _________________ pounds of carbon dioxide in the air every day
from cars alone – not counting truck, heating, trains, etc.
The number of pounds of carbon dioxide in the atmosphere caused by cars in the US every day is:
Carbon footprint: How much carbon our activities are putting into the atmosphere.
Carbon and the Oceans http://www.youtube.com/watch?v=FgEZpX3n5mo&feature=related
According to this NASA film:
How much more carbon does the ocean store compared to the atmosphere?
What does carbon sink mean?
What happens at the ocean’s surface?
What do phytoplankton carry to the ocean floor when they die and descend?
What has this made the ocean floor?
What does upwelling do to carbon?
How much of human-generated carbon has dissolved in the ocean?
The ocean water has been warming up. Can warm water hold more or less carbon than cold water?
Will the ocean become more or less effective at removing carbon from the atmosphere?
On Your Own:
Page 66, Table 3.2: Argon is how many parts ppm in the atmosphere? How about methane? Page 67: According to the ice-core records, carbon dioxide is higher now than at any time in the past ____________years.
What percent of increase in carbon dioxide have seen from the year 2000 to present?