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. Page 2-1

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. Page 2-5

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. Page 2-9