The carbon cycle across rock, ocean, air and life

Grade 9 Science Worksheet

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.

   Using the table, the fast cycle's low end is 1,000 million metric tons a year and the slow cycle's high end is 100 million. How many times larger is the fast end, by Bo's math?

   • 0.1 times
   • 10 times
   • 1,100 times
   • 900 times
3. 2.

   Compare the slow cycle's low end (10 million metric tons a year) with the fast cycle's high end (100,000 million). How many times larger is the fast flow, by Esme's math?

   • 10,000 times
   • 100 times
   • 1,000 times
   • 99,990 times
4. 3.

   NASA (2009): people released about 8.4 billion tons of carbon from fossil fuel, and about half is removed by the fast cycle each year. About how much stays in the air, by Jun's math?

   • About 4.2 billion tons
   • About 0.42 billion tons
   • About 16.8 billion tons
   • About 4.2 million tons

5. Carbon's slow path

   Rain, rock, river, sea floor, limestone, volcano.

6. 4.

   In the ocean, calcium ions combine with bicarbonate. What forms and builds up as limestone, by Kira's reading (NASA)?

   • Calcium carbonate
   • Methane gas
   • Pure carbon dioxide
   • Sodium chloride
7. 5.

   What returns carbon from sea-floor rock to the air over millions of years, by Milo's reading (NASA)?

   • Winter cold squeezes CO₂ out of the sea-floor rock each year
   • Waves wash the limestone up into the clouds
   • Fish eat the limestone and breathe its carbon out
   • Plates carry it down, the rock heats, and volcanoes vent CO₂
9. 6.

   What mainly adds extra CO₂ to the air today, by Noah's reading (NASA)?

   • People breathing out more than in the past
   • Growing crops, which give off CO₂ in sunlight
   • Burning fossil fuels, with some from clearing land
   • Volcanoes erupting more often than in the past
10. 7.

    Why does burning fossil fuels change the carbon cycle, by Pia's reading (NASA)?

    Use the picture in question 6.

    • It moves carbon from the slow cycle into the fast cycle quickly
    • It slows the fast cycle down to the pace of rock
    • It makes brand-new carbon that was not on Earth at any time before
    • It moves carbon from the air back into rock quickly
11. 8.

    Rain, rock, river, sea floor, limestone, volcano. Without people, how would carbon in fossil fuels reach the air, by Ren's reading (NASA)?

    • Slowly, through volcanic activity over millions of years
    • Each day, as waves wash it out of rock
    • Within a lifespan, as animals breathe
    • Within a year, through plant growth
13. 9.

    NOAA: the ocean absorbs about 30% of the CO₂ released into the air. Of 10 billion tons released (model data), about how much is that, by Zee's math?

    • About 13 billion tons
    • About 0.3 billion tons
    • About 7 billion tons
    • About 3 billion tons
14. 10.

    NASA: over millennia, the ocean will absorb up to 85% of the extra carbon. Why does it take so long, by Ari's reading?

    Use the picture in question 9.

    • The ocean is already full of carbon and can take in no more of it
    • Fish must eat the carbon before it dissolves
    • It depends on water moving from the surface to the depths
    • CO₂ cannot dissolve in salt water