The carbon cycle across rock, ocean, air and life

Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

1. Read this first

   Where carbon is and how fast it moves (NASA)

   Part of the cycle	NASA figure
   Carbon stored in rocks	about 65,500 billion metric tons
   Carbon through the slow cycle each year	10 to 100 million metric tons
   Carbon through the fast cycle each year	1,000 to 100,000 million metric tons
   Volcano CO₂ each year	130 to 380 million metric tons
   Human CO₂ each year	about 30 billion tons

2. 1.

   A classmate says volcanoes add more CO₂ than people do. Which reply fits NASA, by Esme's reading?

   • Correct; volcanoes emit about 30 billion tons a year, far more than people do
   • No; volcanoes emit no CO₂ whatsoever, since rock holds very little carbon
   • Correct; human CO₂ joins the slow cycle and takes millions of years to count
   • No; people emit about 30 billion tons a year, 100 to 300 times more than volcanoes
3. 2.

   A student says most of Earth's carbon is in the air. Which reply fits NASA, by Jun's reading?

   • Correct; carbon leaves rock within a few years, so rocks hold little
   • No; most of it is in the plants and animals alive today
   • Correct; the air holds more carbon than rocks and ocean together
   • No; most is in rocks, about 65,500 billion metric tons
4. 3.

   Up in northern winter, down in spring and summer. Model data: the air holds 424 ppm of CO₂, and plants draw out 2 ppm in a month (NASA's August figure). What would it hold after, by Luz's math?

   • About 426 ppm
   • About 212 ppm
   • About 422 ppm
   • About 848 ppm
6. 4.

   NASA gives the fast cycle as 10¹⁵ to 10¹⁷ grams of carbon a year. How many times larger is the high end than the low end, by Milo's math?

   • 10,000 times
   • 32 times
   • 100 times
   • 2 times
7. 5.

   Using 1 billion tons of carbon a year from land use and 8.4 billion from fossil fuels (NASA), about what share comes from land use, by Noah's math?

   Use the picture in question 4.

   • About 84%
   • About 1%
   • About 89%
   • About 11%
8. 6.

   Up in northern winter, down in spring and summer. Which evidence best shows that plants move carbon quickly through the air, by Pia's reading (NASA)?

   • Rocks hold less carbon than living plants hold
   • CO₂ drops each northern spring and climbs each winter
   • Limestone forms on the sea floor within a single season
   • Volcanoes emit far more CO₂ each spring
9. 7.

   Which evidence best supports that fossil-fuel carbon is building up in the air, by Ren's reading (NASA)?

   • The ocean releases more carbon than it takes in
   • Volcanoes emit more CO₂ each year than people
   • About half of each year's fossil-fuel CO₂ stays in the air
   • Fossil-fuel CO₂ turns into limestone rock within a single year
10. 8.

    Rain, rock, river, sea floor, limestone, volcano. Which summary of the slow and fast carbon cycles fits NASA, by Zee's reading?

    • Slow: rocks, 100 to 200 million years; fast: life, about a lifespan
    • Both run through living things at the same pace
    • Slow: life, about a lifespan; fast: rocks, 100 to 200 million years
    • Fast: plants give off CO₂ in sunlight and take it in at night
12. 9.

    Which summary of people's effect on the carbon cycle fits NASA, by Ari's reading?

    • Fuel burning speeds up the slow cycle, so new rock forms faster
    • Burning fossil fuels moves rock carbon to the air far faster than volcanoes
    • Burning fuels moves air carbon back into rock faster than volcanoes
    • People emit less CO₂ than volcanoes, so the cycle is unchanged
13. 10.

    Which summary of the ocean's role fits NASA, by Bo's reading?

    Use the picture in question 9.

    • It takes in the extra carbon within a year or two
    • It now takes in more carbon than it releases, slowly, over millennia
    • It holds most of Earth's carbon, more than rocks
    • It now gives off more carbon to the air each year than it takes back in