FossilsLesson FeedbackCourse Dashboard· Lesson Objectives· T

Fossils
Lesson FeedbackCourse Dashboard
· Lesson Objectives
· The student will investigate and understand the rock cycle as
it relates to the origin and transformation of rock types and how
to identify common rock types based on mineral composition
and textures.
· Key concepts include sedimentary (clastic and chemical)
rocks, scales, diagrams, maps, charts, graphs, tables, and
profiles are constructed and interpreted.
· The student will investigate and understand that many aspects
of the history and evolution of the Earth and life can be inferred
by studying rocks and fossils.
· Key concepts include traces and remains of ancient, often
extinct, life are preserved by various means in many
sedimentary rocks, superposition, cross-cutting relationships,
index fossils, and radioactive decay are methods of dating
bodies of rock, absolute and relative dating have different
applications but can be used together to determine the age of
rocks and structures; and rocks and fossils from many different
geologic periods and epochs are found in Virginia.
·
Geological Time
When we look at human history, we often talk about things in
terms of hundreds or thousands of years. During the majority of
this time we have some sort of written records to analyze. When
we talk about looking at the history of the Earth, and the
evolution of organisms on it, we are looking at time periods
spanning millions and billions of years. Understanding this
portion of history requires detective work: gathering evidence
and making comparisons.

People who study this kind of history have to use a greater time
scale than that used for human history; this time scale is
referred to as the geologic time scale. Think of it like a book,
with the rocks as its pages. Some of the pages are torn or
missing, and the pages are not numbered, but geology gives us
the tools to help us read this book.
Long before geologists had the means to recognize and express
time in numbers of years before the present, they developed the
geologic time scale. This time scale was developed gradually,
mostly in Europe, over the eighteenth and nineteenth centuries.
Earth's history is subdivided into eons, which are subdivided
into eras, which are subdivided into periods, which are
subdivided into epochs. The names of these subdivisions, like
Paleozoic or Cenozoic, may look daunting, but to the geologist
there are clues in some of the words. For example, zoic refers to
animal life, and paleo means ancient, meso means middle,
and ceno means recent. So the relative order of the three
youngest eras, first Paleoozoic, then Mesozoic, then Cenoozoic,
is straightforward.
Fossils are the recognizable remains, such as bones, shells, or
leaves, or other evidence, such as tracks, burrows, or
impressions, of past life on Earth. Scientists who study fossils
are called paleontologists. Remember that paleo means ancient;
so a paleontologist studies ancient forms of life. Fossils are
fundamental to the geologic time scale. The names of most of
the eons and eras end in zoic, because these time intervals are
often recognized on the basis of animal life. Rocks formed
during the Proterozoic Eon may have fossils of relative simple

organisms, such as bacteria, algae, and wormlike animals.
Rocks formed during the Phanerozoic Eon may have fossils of
complex animals and plants such as dinosaurs, mammals, and
trees.
This video shows what the earth was like during the Pre-
Cambrian. Notice how simple the life forms were and where
they all were found:
Now let's compare what life looks like throughout the
Phanerozoic Eon. Notice how life changes.
Sedimentary Rocks
Most of the rocks exposed at the surface of Earth
are sedimentary--formed from particles of older rocks that have
been broken apart by water or wind. The gravel, sand, and mud
settle to the bottom in rivers, lakes, and oceans. These
sedimentary particles may bury living and dead animals and
plants on the lake or sea bottom. With the passage of time and
the accumulation of more particles, and often with chemical
changes, the sediments at the bottom of the pile become rock.
Gravel becomes a rock called conglomerate, sand becomes
sandstone, mud becomes mudstone or shale, and the animal
skeletons and plant pieces can become fossils.
As early as the mid-1600's, the Danish scientist Nicholas Steno
studied the relative positions of sedimentary rocks. He found
that solid particles settle from a fluid according to their relative
weight or size. The largest, or heaviest, settle first, and the
smallest, or lightest, settle last. Slight changes in particle size

or composition result in the formation of layers, also called
beds, in the rock. Layering, or bedding, is the most obvious
feature of sedimentary rocks.
Sedimentary rocks are formed particle by particle and bed by
bed, and the layers are piled one on top of the other. Thus, in
any sequence of layered rocks, a given bed must be older than
any bed on top of it. This Law of Superposition is fundamental
to the interpretation of Earth history, because at any one
location it indicates the relative ages of rock layers and the
fossils in them.
Layered rocks form when particles settle from water or air.
Steno's Law of Original Horizontality states that most
sediments, when originally formed, were laid down
horizontally. However, many layered rocks are no longer
horizontal. Because of the Law of Original Horizontality, we
know that sedimentary rocks that are not horizontal either were
formed in special ways or, more often, were moved from their
horizontal position by later events, such as tilting through pl ate
tectonics or earthquakes.
Rock layers are also called strata (the plural form of the Latin
word stratum), and stratigraphy is the science of strata.
Stratigraphy deals with all the characteristics of layered rocks;
it includes the study of how these rocks relate to time.
This video shows how we use relative age to date rock layers:
More on the Time Scale
How can we add numbers to a time scale based on rock
sediment? How have geologists determined that:
· Earth is about 4.6 billion years old?
· The oldest known fossils are from rocks that were deposited
about 3.5 billion years ago?

· The first abundant shelly fossils occur in rocks that are about
570 million years old?
· The last ice age ended about 10,000 ago?
·
Geologic time scale showing both relative and numeric ages.
Ages in millions of years are approximate
Nineteenth-century geologists and paleontologists believed that
Earth was quite old, but they had only crude ways of estimating
just how old. The assignment of ages of rocks in thousands,
millions, and billions of years was made possible by the
discovery of radioactivity.
Now we can use minerals that contain naturally occurring
radioactive elements to calculate the numeric age of a rock in
years.
As you know, the basic unit of each chemical element is the

atom. An atom consists of a central nucleus, which contains
protons and neutrons, surrounded by a cloud of
electrons. Isotopes of an element are atoms that differ from one
another only in the number of neutrons in the nucleus. For
example, radioactive atoms of the element potassium have 19
protons and 21 neutrons in the nucleus (potassium 40); other
atoms of potassium have 19 protons and 20 or 22 neutrons
(potassium 39 and potassium 41). A radioactive isotope (the
parent) of one chemical element naturally converts to a stable
isotope (the daughter) of another chemical element by
undergoing changes in the nucleus.
The change from parent to daughter happens at a constant rate,
called the half-life. The half-life of a radioactive isotope is the
length of time required for exactly one-half of the parent atoms
to decay to daughter atoms. Each radioactive isotope has its
own unique half-life. Precise laboratory measurements of the
number of remaining atoms of the parent and the number of
atoms of the new daughter produced are used to compute the
age of the rock. For dating geologic materials, four
parent/daughter decay series are especially useful: carbon to
nitrogen, potassium to argon, rubidium to strontium, and
uranium to lead. Age determinations using radioactive isotopes
are subject to relatively small errors in measurement--but errors
that look small can mean many years or millions of years. If the
measurements have an error of 1 percent, for example, an age
determination of 100 million years could actually be wrong by a
million years too low or too high.
Parents and daughters for some isotopes commonly used to
establish numeric ages of rocks.

Isotopic techniques are used to measure the time at which a
particular mineral within a rock was formed. To allow us to
assign numeric ages to the geologic time scale, a rock that can
be dated isotopically is found together with rocks that can be
assigned relative ages because of their fossils. Many samples,
usually from several different places, must be studied before
assigning a numeric age to a boundary on the geologic time
scale.
This video explains how we find the absolute age of a rock or
fossil using half-life:
The geologic time scale is the product of many years of
detective work, as well as a variety of dating techniques not
discussed here. The details will change as more and better
information and tools become available. Many scientists have
contributed and continue to contribute to the refinement of the
geologic time scale as they study the fossils and the rocks, and
the chemical and physical properties of the materials of which
Earth is made.
Fossil Succession

When most people think of fossils, they tend to think of
dinosaurs, but dinosaurs only form a small fraction of the
millions of species that live and have lived on Earth. The great
bulk of the fossil record is dominated by fossils of animals with
shells and microscopic remains of plants and animals, and these
remains are widespread in sedimentary rocks. It is these fossils
that are studied by most paleontologists.
Three concepts are important in the study and use of fossils:
(1) Fossils represent the remains of once-living organisms.
(2) Most fossils are the remains of extinct organisms; that is,
they belong to species that are no longer living anywhere on
Earth.
(3) The kinds of fossils found in rocks of different ages differ
because life on Earth has changed through time.
If we begin at the present and examine older and older layers of
rock, we will come to a level where no fossils of humans are
present. If we continue backwards in time, we will successively
come to levels where no fossils of flowering plants are present,
no birds, no mammals, no reptiles, no four-footed vertebrates,
no land plants, no fishes, no shells, and no animals. The three
concepts are summarized in the general principle called the Law
of Fossil Succession: The kinds of animals and plants found as
fossils change through time. When we find the same kinds of
fossils in rocks from different places, we know that the rocks
are the same age.
The Law of Fossil Succession is very important to geologists
who need to know the ages of the rocks they are studying. The
fossils present in a rock exposure or in a core hole can be used
to determine the ages of rocks very precisely. Detailed studies

of many rocks from many places reveal that some fossils have a
short, well-known time of existence. These useful fossils are
called index fossils.
Today the animals and plants that live in the ocean are very
different from those that live on land, and the animals and
plants that live in one part of the ocean or on one part of the
land are very different from those in other parts. Similarly,
fossil animals and plants from different environments are
different. It becomes a challenge to recognize rocks of the same
age when one rock was deposited on land and another was
deposited in the deep ocean. Scientists must study the fossils
from a variety of environments to build a complete picture of
the animals and plants that were living at a particular time in
the past.
If we look at the Law of Fossil Succession together with the
concept of evolution, we see that first there were simple single
celled organisms, then more complex organisms, then movement
from the oceans onto land by both plants and animals, then
formation of larger animals on land. We can study the
transitions of evolution through studying the fossil record--
though the record will not always be complete.
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Bonus Content (This section is not required)
If you are interested in more information about some of the
topics from the lesson OR if you need help with some of the
questions, you can watch these OPTIONAL (you can watch if
you want but they are not required) videos for help!

Watch the following videos to find out more information on
what life was like during the Paleozoic, Mesozoic, and
Cenozoic time periods.
Paleozoic Life
Mesozoic Life
Cenozoic Life (Time period we are in right now)
· Grading Rubric
Rubric Earth Science Lesson 8
Note: For this class it is necessary to post each question, then
the work/explanation, then the answer. Failure to do so will
result in asking for a revision. No grade will be given for
incomplete work.
Mastery of this lesson will be determined when your total points
are 8 or higher. Revisions will be requested when your total
points are below 8. Points are earned according to the chart
below.
10: A total score of 10 on your first submission, or within the
first revision.
9.5: A total score of 9.5, or all questions are correct after the
first revision.
9: A total score of 9.
8.5: A total score of 8.5.
Short Answer
5 points total
Answers are clearly written, accurate, and student uses their
own words.
1 points awarded
Answer is clearly written. May have 1 factual omission or error.
0.5 point awarded
Answer is not clearly written. There are several factual

omissions or errors.
0 points awarded
Apply Your Knowedge
3 points total
(1 point per question)
Questions are thoroughly answered in complete sentences and in
student’s own words. URLs are included for outside research.
1 point awarded
Questions are answered but may have incomplete responses or
contain minor errors. Responses are in the student’s own words.
URLs are included for outside research.
0.5 point awarded
Questions contain inaccurate information and/or are not written
in the student’s own words. URLs for outside research are not
provided.
0 points awarded
Essay
2 points total
Question is answered thoroughly describing how the meteor
killed the dinosaurs and at least 2 pieces of evidence are
provided.
2 points awarded
Question is answered partially and/or one piece of evidence is
missing.
1 point awarded
Question is not answered thoroughly and evidence is not
provided.
0 points awarded
· Assignment

Do not submit text that you have copied from sources, including
websites. All of your work should be in your own words. Using
copied text would be considered plagiarism. For more
information, review our page on Plagiarism and Citation. Cite
the complete web page source under each answer. Always put
the question on top of the answer, and answer in complete
grammatically correct sentences.
Many of these answers will require Internet research to answer.
Make sure you rewrite all answers into your own words and be
mindful of our page on Plagiarism and Citation.
Short Answer
1. How are sedimentary rocks formed?
2. Why are fossils found in sedimentary rocks instead of other
rock types? Why can't they be found in igneous or
metamorphic?
3. How are radioactive isotopes used to determine the age of
rock? Use the word half life in your answer. Explain how it
works.
4. How can the Law of Superposition tell us how old one fossil
is compared to another found in the same general area?
5. What are fossils?
Apply Your Knowledge
6. What are index fossils? Give at least 2 characteristics of
index fossils.
7. What Cenozoic fossils have been found in the region where
you live? Name at least two and the location where they were
found. Remember Cenozoic is the time period we are in right

now. Be sure you cite your source.
8. What Mesozoic fossils have been found in the region where
you live? Name at least two and the location where they were
found. Be sure you cite your source.
Essay
9. Write a paragraph about the asteroid theory of dinosaur
extinction. Be sure to include at least 2 pieces of evidence to
support this idea--Make sure to use iridium as one piece of
evidence & explain why it is so important.
Nonrenewable and Renewable Resources
· The student will investigate and understand the differences
between renewable and nonrenewable resources.
· key concepts include fossil fuels, minerals, rocks, water, and
vegetation
· advantages and disadvantages of various energy sources
· resources found in Virginia
· making informed judgments related to resource use and its
effects on Earth systems
· environmental costs and benefits.
·
To support the way human beings live, it is necessary to use
certain resources in the environment. When these resources
cannot be replenished in a short amount of time, they are
referred to as nonrenewable resources. Resources which can be
replenished in a short amount of time are called renewable
resources.
Nonrenewable Resources
The resources most commonly considered "nonrenewable" are

oil, natural gas, coal, and uranium. Fossil fuels (oil/petroleum,
natural gas/propane, coal) can take millions of years to form,
and at current rates will be depleted long before any more will
form. Uranium is not a fossil fuel, but the special kind used in
nuclear plants is very rare.
See the difference between Nonrenewable and Renewable
Resources
Power plants which run off of nonrenewable resources use the
nonrenewable resource to generate heat. The heat is used to boil
water, which turns a turbine, and the turbine generates
electricity.
Fossil fuels were formed from organic material which was
deposited on the bottom of the ocean floor a long time ago,
millions of years before the dinosaurs. This organic material
became part of the sedimentary rock, and as more layers were
added and the pressure on top built high enough to create
intense heat these organic materials went through chemical
changes, becoming different sorts of carbon based solids,
liquids, and gases.
Oil
In most places, the organic materials that were trapped under
the sediment layers were heated for millions of years until they
formed into a thick, black liquid called oil. This oil seeped
toward the surface, but was sometimes stopped by layers of
impermeable stone. These layers of stone are called
"capstones", and it is under these capstones that we find pockets
of oil today.
The top five oil producing states are Texas, Alaska, California,
Louisiana and Oklahoma. However the U.S. has only been
producing about 40% of the oil it needs, so the majority of oil is

imported. In 2000, the U.S. spent 109 billion dollars on
importing oil.
Oil is used to make heating oil, as well as gasoline, diesel, and
jet fuel. Oil is also used in the making of some plastics and
other products (such as crayons and bubble gum).
This video shows how oil and natural gas are formed:
Natural Gas
In some places when oil formed the heat and pressure continued
to build until that liquid was transformed into a gas. This
natural gas did much as the oil did, and found ways to seep to
the surface. However, again like the oil, this gas was stopped by
capstones, which is where we find natural gas today.
Natural gas is an odorless flammable gas, most often used for
heating homes.
Coal
Coal is a combustable solid which is mined from the ground.
Coal formed much the same way as the oil and gas did, though
it is thought that sulfurous seas covered the vegetation and
mixed into the base organic materials, adding some extra
elements to the process. As pressure is applied over time by the
layers of rock above it, coal goes through many stages of
development first forming peat, then lignite (brown coal), then
sub-bituminous, bituminous and anthracite coal. The pinnacle of
coal evolution is graphite, but it is not used as a fuel since it is
hard to ignite.

Coal may be the biggest fossil fuel in the United States. It is
relatively inexpensive: 23 of the 25 U.S. power plants with the
lowest operating costs are using coal. Coal based plants are
responsible for over half of the U.S. electrical power. Also, the
U.S. has plenty of coal; it is estimated that the U.S. could
produce energy for itself for at least another 200 years using the
coal reserves in the U.S. However coal has tremendous negative
environmental impacts, from dangerous and damaging mining
methods to the smoke (containing sulfur and carbon dioxide)
which is released when it is burned.
Coal has been mined in 26 of the 50 states in the U.S., but the
four states with the largest coal reserves are: Wyoming, West
Virginia, Illinois, and Montana.
Coal in the United States
According to the Energy Information Administration, a division
of the U.S. Dept. of Energy, there are three main coal producing
regions of the U.S.:
Appalachian Coal Region:
Interior Coal Region:
Western Coal Region:
* Over half of the coal produced in the U.S. is produced in the
Western Coal Region.
* Wyoming is the largest regional coal producer, as well as the
largest coal-producing state in the nation.
* Large surface mines.
* Some of the largest coal mines in the world.
· * More than one-third of the coal produced in the U.S. is
produced in the Appalachian Coal Region.
* West Virginia is the largest coal-producing state in the region,
and the second largest coal-producing state in the U.S.

* Large underground mines and small surface mines.
* Coal mined in the Appalachian coal region is primarily used
for steam generation for electricity, metal production, and for
export.
* Texas is the largest coal producer in the Interior Coal Region,
accounting for almost one-third of the region’s coal production.
* Mid-sized surface mines.
* Mid- to large-sized companies.
Uranium
Uranium is a relatively abundant element, but only a particular
kind of uranium (U-235) is used in nuclear power plants. This
type of uranium has atoms which are more easily split apart,
and it is in splitting these atoms that energy is released. The
majority of uranium in the U.S. in mined in the western states.
It provides about 19% of the power in the U.S.
According to EIA, after processing "[t]he uranium fuel is
formed into ceramic pellets. The pellets are about the size of
your fingertip, but each one produces the same amount of
energy as 150 gallons of oil."
Compared to fossil fuels, uranium is a clean fuel. It still
produces waste, however, some of which is mildly radioactive.
Renewable Resources
When speaking of renewable resources, mostly people are
referring to wind, solar, biomass, geothermal, and hydro power.
You will be asked to research and discuss several of these in the
assignment below.
Given that we know nonrenewable resources are limited, why
don't we use more renewable energy? According to the U.S.

DOE:
In the past, renewable energy has generally been more
expensive to use than fossil fuels. Plus, renewable resources are
often located [in] remote areas and it is expensive to build
powerlines to the cities where they are needed. The use of
renewable sources is also limited by the fact that they are not
always available (for example, cloudy days reduce solar energy,
calm days mean no wind blows to drive wind turbines, droughts
reduce water availability to produce hydroelectricity).
The production and use of renewable fuels has grown more
quickly in recent years due to higher prices for oil and natural
gas, and a number of State and Federal Government incentives,
including the Energy Policy Acts of 2002 and 2005. The use of
renewable fuels is expected to continue to grow over the next 30
years, although we will still rely on non-renewable fuels to meet
most of our energy needs.
One of the larger prices attached to renewable energy resources
is the price of land. Wind farms take many acres of land in
order to produce energy. Horse Hollow Wind Energy Center in
Texas is the world's largest wind farm, it has 421 wind turbines
which can power 220,000 homes per year; this wind farm takes
up nearly 47,000 acres. Solar cells have a similar problem, since
the sun's rays only deliver a small amount of energy to any
single spot: It is the energy collected over a wide area which
makes the technology useful. Despite large land or space needs,
however, there are fewer environmental impacts from renewable
energy resources than tend to exist from nonrenewable ones.
Other Resources and Sustainability
Generally renewable and nonrenewable resources are discussed
in reference to energy production. However there are many
other renewable and nonrenewable resources. For example, the

fish in a bay would be an important, potentially renewable, food
resource. Any mineral in an area might be an important
nonrenewable resource: This could be tin, silver, gold,
diamonds, salt, limestone...the list is almost endless. Any item
in an area can be assessed as renewable or nonrenewable based
on the method of its extraction, the rate of use, and the rate of
replenishment. For example, if we timber land for lumber, but
do so at a rate that leaves us with no more trees before we've
met our need for lumber, this is not sustainable (hence, not a
renewable resource, even though we can grow more trees).
Being aware of whether a resource is renewable or not is only a
part of responsible resource management. A nonrenewable
resource may be extracted and used responsibly, and a
renewable resource can be extracted in ways that are a nuisance:
New studies are often being conducted to give us information on
how to best utilize these resources the Earth grants us.
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Watch this video to see how coal is formed and the different
types of coal.
Check out these facts about Uranium

See how biomass energy works:
This video discusses how geothermal energy works:
See how a dam creates energy through hydropower:
· Grading Rubric
incomplete work.
points are below 8. Points are earned according to the chart
below.
first revision.
first revision.
Short Answer
4 points total
Answer is clearly written and accurate. Answer is based on the
lesson content.
0.5 points
Answer is clearly written. May have 1 factual omission or error.
0.25 points
Answer is not clearly written. There are several factual
omissions or errors.
0 points
Apply Your Knowledge Questions
6 points total

student’s own words. URLs are included for outside research.
1 points
0.5 points
provided.
0 points
· Assignment
Short Answer
1. If fossil fuels are formed from organic materials compacted
on the ocean floor, what does that tell us about the Appalachian
mountain region? What was in the Appalachian region at one
point in time to form fossil fuels?

2. What are three of the top oil producing countries of the
world?
3. From what you've learned about the formation of oil, where
are there most likely to be pockets of undiscovered oil today?
Add reasons why you think oil will be found in that place based
on where/how oil is formed.
4. Which fossil fuel is the most abundant in the U.S.?
5. Find four products that are made from oil (petroleum) and list
them here. Cite your sources.
6. What do the machines known as "digesters" do?
7. If natural gas is odorless, why is it possible to smell when a
house has a gas leak?
8. What is propane? What are some of its uses?
9. Why is coal's release of sulfur and carbon dioxide potentially
dangerous?
10. The lesson mentioned that wind farms need a lot of land.
What is another negative impact wind farms can have?
11. Can cattle or other livestock graze on the land where a
windfarm is located?
12. Hydropower uses the flow of a river or the ebb and flow of
the tides to create energy. Tell me about one specific way we
capture hydropower. Cite your source.
13. What is geothermal energy?

14. Give me a specific way in which geothermal energy can be
harnessed. Cite your source.
Начало формы
Atmosphere
· The student will investigate and understand the origin and
evolution of the atmosphere and the interrelationship of
geologic processes, biologic processes, and human activities on
its composition and dynamics.
· key concepts include scientific evidence for atmospheric
changes over geologic time
· current theories related to the effects of early life on the
chemical makeup of the atmosphere
· comparison of the Earth’s atmosphere to that of other planets
· atmospheric regulation mechanisms including the effects of
density differences and energy transfer
· potential atmospheric compositional changes due to human,
biologic, and geologic activity
· What is the atmosphere? What does it do? How was it
formed?
Watch this video to give you a preview of what we will learn in
this lesson.
Here are 25 Amazing Facts about our atmosphere!
When the Earth was first formed, the gases released by various
processes were probably stripped away by the Sun's solar winds,
but eventually a state was reached where the atmosphere
remained. This atmosphere would have seemed very thick
compared to today's atmosphere, with about 80% of it made up

of water vapor. This water vapor would have been released as
rainfall, and created the oceans.
Water sediments have been found that date back as far as 3.8
billion years ago. Studying these sediments can tell us much
about the content of the Earth's atmosphere . Just after our first
known early life forms, at about 3.5 billion years ago, the
atmosphere seems to have stabilized as a nitrogen rich matter.
The balance of living organisms, shifting land masses, and the
content of the atmosphere slowly changed until there was an
oxygen component to the atmosphere, which grew. Today's
atmosphere is mostly nitrogen (about 78% in dry air) and
oxygen (about 21% in dry air), with some other elements, such
as carbon, also getting into the mix.
There was a long period of time when Earth's atmosphere did
not contain oxygen. It is theorized that many of the processes
where organisms now use oxygen at one time used sulfur
instead. Studying the chemical make-up of rock beds can give
scientists information about what compositions were available
in the air. In the past, there was probably a lot more carbon
dioxide in the atmosphere, but since carbon dioxide is water
soluble, it gets washed down by rain. Also, plant life uses
carbon dioxide during photo-synthesis, and releases oxygen,
which helps explain the growing oxygen component.
Unlike several of our neighboring planets, the Earth's
atmosphere has a way of balancing the amount of carbon
dioxide in the atmosphere: The carbon cycle, or the carbon-
silicate cycle. As rain falls, it pulls carbon dioxide from the air
and deposits it into the oceans. Sea creatures use the carbon
(usually in combination with calcium and other minerals) and
then when sea creatures die, the carbon compounds wind up as
sediment at the bottom of the ocean. The ocean floor is

seismically active, which brings these compounds into the
mantle, where they can be re-released only by volcanic activity.
Atmospheric Layering
The atmosphere has five distinct layers, each with different
chemical compositions, different temperatures, and different
densities. The layers are known as the troposphere, the
stratosphere, the mesosphere, the thermosphere, and the
exosphere.
The troposphere is the layer closest to the ground. It extends
about 12 miles above the Earth's surface at the equator, but only
about 4 miles above the Earth's surface at the poles. The
troposphere has the right composition, pressure, and
temperatures to make life on Earth (as we know it) possible.
The further away from the Earth one goes, or the higher the
elevation, the thinner and colder the air gets. Since the air is
colder up higher, and heat rises, this means that there is likely
to be a lot of air movement in this layer. It is also where all
weather takes place.
See the different layers of the atmosphere and what each one
does:
Volcanic Effects
As mentioned earlier with the carbon-silicate cycle, magma is
one repository of dissolved gases. It is also one of our largest
sources of water. Magma is compacted into an extremely dense
state under the surface of the Earth, such that when it is
explosively released it takes up much more space on the surface
of the Earth than it does underground. According to the U.S.
Geological Survey, "if one cubic meter of 900°C rhyolite
magma containing five percent by weight of dissolved water"
were brought up to the surface in an instant, that "one cubic
meter of magma now would occupy a volume of 670 m3 as a

mixture of water vapor and magma at atmospheric pressure."
The biggest release from a volcanic eruption is that of water
vapor, but there can also be large amounts of carbon dioxide
and sulfur dioxide. Aside from the immediate dangers of
eruptions, scientists have found that volcanic eruptions can also
affect climate.
"Measurements from recent eruptions such as Mount St. Helens,
Washington (1980), El Chichon, Mexico (1982), and Mount
Pinatubo, Philippines (1991), clearly show the importance of
sulfur aerosols in modifying climate, warming the stratosphere,
and cooling the troposphere. Research has also shown that the
liquid drops of sulfuric acid promote the destruction of the
Earth's ozone layer." (USGS, "Volanic Gases and Their
Effects")
The Human Factor
There has been some concern over the effect that human activity
can have on the atmosphere. Modern man has developed many
technological advances that release gases into the atmosphere
that would otherwise not be present, or release gases in greater
quantities than would otherwise occur. If this has an effect on
the climate of the Earth it could be dangerous, over the long
term, to the delicate balances that support life.
"Scientists have calculated that volcanoes emit between about
130-230 million tonnes (145-255 million tons) of CO2 into the
atmosphere every year (Gerlach, 1999, 1991). This estimate
includes both subaerial and submarine volcanoes, about in equal
amounts. Emissions of CO2 by human activities, including
fossil fuel burning, cement production, and gas flaring, amount
to about 27 billion tonnes per year (30 billion tons) [ ( Marland,
et al., 2006) - The reference gives the amount of released

carbon (C), rather than CO2, through 2003.]. Human activities
release more than 130 times the amount of CO2 emitted by
volcanoes--the equivalent of more than 8,000 additional
volcanoes like Kilauea (Kilauea emits about 3.3 million
tonnes/year)! (Gerlach et. al., 2002)." (USGS, "Volanic Gases
and Their Effects")
For more info: https://volcanoes.usgs.gov/vhp/gas_climate.html
_____________________________________________________
______________________________________
See what the formation of the atmosphere might have looked
like:
How does the earth's atmosphere compare to the other planets in
our solar system?
Venus
Mars
The Outer Planets
What does the atmosphere do?
Why is there life on earth? What does this have to do with
Goldilocks?
See how heat is transferred in the atmosphere through
convection currents:

What is air pressure, how is the uneven heating of the
atmosphere important, and how does it impact weather?
What do humans do to impact the atmosphere?
What happens if Earth loses its atmosphere?
· Grading Rubric
incomplete work.
points are below 8. Points are earned according to the char t
below.
first revision.
first revision.
Short answer
Total content points= 8
All parts of all questions are answered in complete sentences.
1 points each
Questions are answered in complete sentences. Not all parts of
each question are answered.
0.5 points each

Questions are not answered in complete sentences and/or are
missing responses for questions.
0 points
Total content points=2
the student’s own words. URLs are included for outside
research.
1 point each
0.5 points each
provided.
0 points
· Assignment

Short Answer
1. Find out a little more about the layers of the atmosphere.
a. Which layer is the largest? How large is it?
b. Where is the ozone layer located? Why is the ozone layer
important?
c. What is the outermost layer called? About how far above the
Earth does it reach?
2. What is the atmosphere of Venus like, and how does it
compare with Earth's atmosphere?
3. What is the atmosphere of Mars like, and how does it
compare with Earth's atmosphere?
4. How are the atmospheres of the inner planets different from
the atmospheres of the gas giants?
5. What is the "Goldilocks Effect" when discussing Earth?
6. One important thing that happens in Earth's atmosphere is
known as heat transfer. In this context, find out what convection
is and tell me briefly about it here. Explain why this movement
occurs.
7. About what percentage of the atmosphere is made up of water
vapor today?
8. What is atmospheric pressure?
9. What does it mean when barometric pressures rise and fall?
What is the weather like when it rises? What is the weather like

when it falls?
10. Name two things humans can do to minimize the impact
their technologies have on the atmosphere.
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