Carbon on the Move
Activity 2
Following a homework research assignment on how carbon atoms cycle through the
earth’s ecosystems and the formation and use of fossil fuels, students identify what they
know and think they know about the earth’s carbon cycle (on a K-W-L chart). After a class
discussion where students generate a story of an imaginary carbon atom as it moves
through Earth’s ecosystems and carbon reservoirs, students write down what they have
learned about the carbon cycle (on the K-W-L chart) and complete a carbon-cycle puzzle.
Objectives
After these activities, students will be able to identify respiration and photosynthesis as key
processes that move carbon through the earth’s biosphere and ecosystems, describe how
human caused changes in land use and burning of fossil fuels are key activities that alter
the movement of carbon and the composition of earth’s atmosphere, explain that organic
matter buried deep enough may be reformed by pressure and heat into fossil fuels, and
understand that all organisms in the biosphere are linked to each other and to their
physical environments by the transfer and transformation of matter.
Standards
Students will develop basic explanations for natural phenomena, interest in global issues,
and the ability to ask good questions and explore and explain related science concepts.
Students will address standards 6.1, 6.2, 9.4, 9.5, 9.7, 9.8, 9.9, scientific inquiry, and
scientific literacy from Connecticut’s Core Science Curriculum Framework.
Time
The homework assignment from Activity 1, which will require one to several days
depending on how readily students have access to the Internet and whether the teacher
requires research on the Internet, is a prerequisite for this activity.
In-class time, one 45-minute class period.
Materials
One copy of the handout Carbon Is (almost) Everywhere! per student for the Activity 1
homework assignment
One copy of the K-W-L chart and a set of puzzle pieces per teams of two
Props needed for the carbon cycle discussion (see Table 2a)
Method
Preparation
Copy onto card stock and cut out enough puzzle sets for teams of two. For multi-year
use, you may want to laminate the puzzles prior to cutting them out.
Copy all other handouts.
This lesson continues from the homework assignment The Carbon Cycle from Activity 1,
which uses the student reading from this activity.
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In teams of two, have the students write down on the K-W-L chart three to five things that
the team is absolutely sure they know about the carbon cycle. Then have them write down
three to five things that the team members want to know about the carbon cycle.
Encourage students to find answers to what they want to know during the following
discussion.
As a class, generate a story of an imaginary carbon atom as it moves through Earth’s
ecosystems. Have students contribute parts of the stories they developed for homework.
Use props as suggested in Table 2a to illustrate the story. Encourage students to use this
discussion to clarify what they know or think they know about the carbon cycle.
Following the discussion, have the teams write down on the K-W-L chart three to five things
that they learned about the carbon cycle. Once completed have the student teams hand in
their K-W-L charts as a “ticket” to receive the puzzle pieces. Have the students complete
the puzzle and accompanying questions.
Table 2a. Samples of props for discussion of carbon cycle stories
Items Containing Carbon
Showing Movement of Carbon
wood
living plant
(photosynthesis and respiration)
bottle of air
(labeled as such)
picture of people eating
and exercising (respiration)
bottle of soda
open can of soda (diffusion)
vegetable
burning wood splint
vegetable oil
lit Bunsen burner
motor oil
Compost or decayed leaf litter
Background Information
Carbon has an atomic number of six and has four electrons in its valence shell. Since eight
electrons are needed to fill a valence shell, carbon can form four bonds with other atoms.
Each bond incorporates one of the carbon atom's electrons and one of the bonding atom's.
Carbon atoms can form many different shapes such as chains, branched chains, or rings.
Fossil fuels, or hydrocarbons, consist of chains of carbon atoms with
the subsequent empty carbon bonds filled with hydrogen atoms. For
example, the simplest hydrocarbon, methane or CH4, consists of one
carbon atom bonded to four hydrogen atoms and octane, an average
gasoline molecule, is C8H16 (see graphic).
Substances such as sugars, starches, and cellulose - in short,
carbohydrates - and fats and proteins are formed when carbon atoms
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bond with each other and with combinations of other atoms such as oxygen, hydrogen, and
nitrogen.
Carbon is also found in many other substances as it makes it’s way through the carbon
cycle. A few examples include carbon dioxide (CO2), a gas in Earth’s atmosphere;
bicarbonate salts, which contain the compound HCO3 and are found in the oceans; and
carbonate rocks, which contain CO3 and include limestones and dolomites.
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K-W-L Chart
Name(s)
K
What I know
Date
W
What I want to know
1.
2.
3.
4.
5.
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L
What I learned
CARBON IS (almost) EVERYWHERE!
Carbon is found in a wide variety of materials. It is in the food you eat, the air you breathe, the
soda you drink, the baking soda that you cook with, many rocks we build with, and the gasoline
that fuels your car. It is even in you! Depending on how carbon atoms link with other atoms, they
can form gases such as carbon dioxide and methane (natural gas), liquids such as gasoline and
vegetable oil, or solids such as wood or coal.
Carbon atoms frequently move from place to place, change their chemical partners, and change
their physical state. Most of this happens within a relatively short amount of time but some
processes take millions of years.
Carbon moves quickly from place to place. . .
Each day, plants absorb carbon dioxide (a
gas composed of one carbon and two
oxygen atoms) from the air. Through
photosynthesis they convert it and water
into sugars, starches, and cellulose.
Through the food chain, this carbon moves
into all other living things. (You use it to
make the fats and proteins that your body
needs.) Imagine that! A good part of the
stuff that makes up plants and animals -and you -- used to be floating in the air!
Photosynthesis, the food chain, decay, and respiration all
move carbon through the earth’s ecosystems.
At the same time, burning anything with
carbon in it causes carbon to combine with oxygen, move into the atmosphere, and take the
form of the gas carbon dioxide. This happens when we burn dead plants and animals, when our
bodies burn food for energy, or when dead plants and animals decay. Living plants also release
carbon to the atmosphere through a process called respiration.
. . .or slowly.
Over millions of years, some plant and animal
materials escaped decomposition and instead
were buried under layers of sand and silt.
Slowly, the sugars, starches, cellulose, fats, and
proteins in the materials came under high
pressure and heat as they were buried deeper
and deeper underground. At the same time,
they were exposed to various chemical
reactions and slowly changed into fossil fuels
such as crude oil, natural gas, and coal.
The formation of fossil fuels moved large amounts of
Over millions of years, this process drew
carbon from the atmosphere to underground.
enormous amounts of carbon dioxide out of our
atmosphere and buried the carbon in fossil fuels deep under the ground.
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Today, less carbon is being removed from the atmosphere. . .
Humans are affecting how carbon cycles
between the atmosphere and earth’s
plants and animals. Humans are
increasingly altering the land that we
inhabit, burning vast tracts of forests,
paving over land that once grew plants, and
replanting land with different crops, trees,
and grasses than originally existed. All
these activities change the ability of the
earth’s plants and animals to cycle carbon
dioxide out of the atmosphere.
Changing land use is causing more CO2 to stay in the
atmosphere.
Some activities, such as growing new trees,
increase how much carbon is absorbed.
Many other activities decrease how much
carbon is absorbed. Although there is still a
lot to learn about how different plants
absorb carbon dioxide, the total of all
current activities are causing more carbon
dioxide to stay in the atmosphere.
. . . and humans are adding more.
At the start of the industrial revolution
humans began to burn fossil fuels for the
power they provide. This burning of fossil
fuels has moved a large part of the
carbon that was in long-term storage
underground back into our atmosphere
as carbon dioxide. Each year, as our use
of fossil fuels for energy keeps increasing,
we move larger amounts of carbon back
into our atmosphere as carbon dioxide.
Human use of fossil fuels is pumping carbon from
underground back into our atmosphere as carbon dioxide.
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Why changing levels of carbon in the earth’s atmosphere affects you.
Atmospheric carbon dioxide acts like a
greenhouse.
Carbon dioxide is a gas that can act like a
greenhouse. In our atmosphere, it helps hold some
of the sun’s energy within the earth’s biosphere and
keeps our planet at a livable temperature.
Increasing the level of carbon dioxide in our
atmosphere causes our planet to hold more of the
sun’s energy within the earth’s biosphere. This
appears to be increasing the average temperature of
the earth. (People refer to this as Global Warming.)
This may also be altering the earth’s climates in
unexpected ways. (People refer to that as Global
Climate Change.)
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Name(s)
Date
Puzzle Instructions
This puzzle can be put together so that it looks fine but the concepts shown are wrong. It is your
job to put the puzzle together so that the concepts shown all fit together accurately.
Use information provided in the reading and on the puzzle to complete the following.
1) Look at the diagram on your puzzle that represents the formation of coal and oil.
Write down in which state (gas, liquid, or solid) the carbon is during each stage of
transformation.
Write down at which stage(s) photosynthesis is occurring and which gases are being
taken in and given off.
2) The puzzle shows humans moving carbon from fossil fuels into the atmosphere as carbon
dioxide. Give two examples of other human activities that contribute to increased levels of
carbon dioxide in our air.
3) Over millions of years, some plant and animal materials escaped decomposition and instead
were buried under layers of sand and silt. Circle which of the following is true?
a. Over millions of years, this process drew enormous amounts of oxygen out of our
atmosphere and buried it in fossil fuels deep under the ground.
b. Over millions of years, this process drew enormous amounts of carbon dioxide out of our
atmosphere and buried the carbon in fossil fuels deep under the ground.
c. Over millions of years, this process drew enormous amounts of water out of our
atmosphere and buried it in fossil fuels deep under the ground.
4) Burning anything with carbon in it causes the carbon to combine with oxygen to form carbon
dioxide. Circle each example that illustrates this.
a. A forest fire.
b. Burning calories by jogging.
c. Decaying leaf litter on a forest floor.
d. A tree using sugar in its sap to create a new leaf.
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