Page 32 - 新思维科学学生用书9 样章

1.3 The carbon cycle

Continued

the correct place. For example, if the number is 1, then all the carbon atoms in the air
move into a green plant, as a result of photosynthesis. If the number is 3, then all the

carbon atoms in a green plant move into an animal.
You can keep a record of how many carbon atoms are in each place after each roll of
the die.

Questions
1 In this model, all the carbon atoms in one place move to another place at the

same time. Is that what happens in the real carbon cycle? If not, how could you
modify this model to make it a better representation? If you can, try out your
suggestion on your model.
2 Predict what would happen to the carbon atoms if one of the processes

stopped completely – for example, combustion. If you can, try it out on your
model.

The carbon cycle is a complicated diagram. What can you do to help you to
remember it?

Questions
3 If you drew a carbon cycle to show what was happening before humans were present on Earth,

how would it differ from the carbon cycle diagram above?
4 Explain why fossil fuels are non-renewable resources.

Summary checklist

I can describe the carbon cycle, including photosynthesis, respiration, feeding,
decomposition and combustion.
I can explain how these processes affect the concentration of carbon dioxide in
the air.

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