The carbon cycle across rock, ocean, air and life
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
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 A classmate says volcanoes add more CO₂ than people do. Which reply fits NASA, by Esme's reading?
- 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
- Correct; volcanoes emit about 30 billion tons a year, far more than people do
- No; people emit about 30 billion tons a year, 100 to 300 times more than volcanoes
A student says most of Earth's carbon is in the air. Which reply fits NASA, by Jun's reading?
- No; most of it is in the plants and animals alive today
- Correct; the air holds more carbon than rocks and ocean together
- Correct; carbon leaves rock within a few years, so rocks hold little
- No; most is in rocks, about 65,500 billion metric tons
A yearly CO₂ wiggle
Up in northern winter, down in spring and summer.
A student says the yearly CO₂ wiggle comes from volcanoes. Which reply fits NASA, by Kira's reading?
- No; northern plants draw CO₂ down in spring and summer, and decay returns it
- Correct; the ocean freezes over each winter and stops trading carbon
- Correct; volcanoes erupt each spring and then quiet down each winter
- No; plants release CO₂ in summer and take it in during the winter
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 422 ppm
- About 848 ppm
- About 212 ppm
- About 426 ppm
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?
- 2 times
- 10,000 times
- 32 times
- 100 times
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)?
- Limestone forms on the sea floor within a single season
- Volcanoes emit far more CO₂ each spring
- Rocks hold less carbon than living plants hold
- CO₂ drops each northern spring and climbs each winter
Which evidence best supports that fossil-fuel carbon is building up in the air, by Ren's reading (NASA)?
- Volcanoes emit more CO₂ each year than people
- The ocean releases more carbon than it takes in
- Fossil-fuel CO₂ turns into limestone rock within a single year
- About half of each year's fossil-fuel CO₂ stays in the air
Rain, rock, river, sea floor, limestone, volcano. Which summary of the slow and fast carbon cycles fits NASA, by Zee's reading?
- Both run through living things at the same pace
- Fast: plants give off CO₂ in sunlight and take it in at night
- Slow: life, about a lifespan; fast: rocks, 100 to 200 million years
- Slow: rocks, 100 to 200 million years; fast: life, about a lifespan
Which summary of people's effect on the carbon cycle fits NASA, by Ari's reading?
- People emit less CO₂ than volcanoes, so the cycle is unchanged
- Burning fuels moves air carbon back into rock faster than volcanoes
- Burning fossil fuels moves rock carbon to the air far faster than volcanoes
- Fuel burning speeds up the slow cycle, so new rock forms faster
Which summary of the ocean's role fits NASA, by Bo's reading?
Use the picture in question 9.
- It holds most of Earth's carbon, more than rocks
- It now takes in more carbon than it releases, slowly, over millennia
- It takes in the extra carbon within a year or two
- It now gives off more carbon to the air each year than it takes back in