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?
- 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
- No; volcanoes emit no CO₂ whatsoever, since rock holds very little carbon
- Correct; volcanoes emit about 30 billion tons a year, far more than people do
A student says most of Earth's carbon is in the air. Which reply fits NASA, by Jun's reading?
- No; most is in rocks, about 65,500 billion metric tons
- 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
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?
- Correct; the ocean freezes over each winter and stops trading carbon
- No; plants release CO₂ in summer and take it in during the winter
- Correct; volcanoes erupt each spring and then quiet down each winter
- No; northern plants draw CO₂ down in spring and summer, and decay returns it
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 212 ppm
- About 422 ppm
- About 848 ppm
- About 426 ppm
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?
- About 11%
- About 1%
- About 84%
- About 89%
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)?
- Volcanoes emit far more CO₂ each spring
- CO₂ drops each northern spring and climbs each winter
- Rocks hold less carbon than living plants hold
- Limestone forms on the sea floor within a single season
Model data: carbon leaves a rock reservoir at 100 million tons a year and enters it at 100 million tons a year. What does that show, by Tala's reading?
- The reservoir gains about 200 million tons of carbon a year
- The reservoir is in balance, neither gaining nor losing
- Carbon has stopped moving through it
- The reservoir is losing carbon quickly
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
- Fast: plants give off CO₂ in sunlight and take it in at night
- Both run through living things at the same pace
- Slow: life, about a lifespan; fast: rocks, 100 to 200 million years
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 fossil fuels moves rock carbon to the air far faster than volcanoes
- Burning fuels moves air carbon back into rock 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 now gives off more carbon to the air each year than it takes back in
- It holds most of Earth's carbon, more than rocks
- It takes in the extra carbon within a year or two
- It now takes in more carbon than it releases, slowly, over millennia