The carbon cycle across rock, ocean, air and life
Grade 9 Science Worksheet
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 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
- 99,990 times
- 100 times
- 1,000 times
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 million tons
- About 0.42 billion tons
- About 16.8 billion tons
- About 4.2 billion tons
Carbon's slow path
Rain, rock, river, sea floor, limestone, volcano.
In the ocean, calcium ions combine with bicarbonate. What forms and builds up as limestone, by Kira's reading (NASA)?
- Methane gas
- Calcium carbonate
- Pure carbon dioxide
- Sodium chloride
NASA: about 80% of carbon-containing rock forms from calcium carbonate. Where does the other 20% come from, by Luz's reading?
- Carbon that fell to Earth from space as meteorites over long ages
- Carbon from living things buried in mud, making rock like shale
- Ice that froze CO₂ from the air into stone
- Volcanic ash that holds no carbon from living things
What returns carbon from sea-floor rock to the air over millions of years, by Milo's reading (NASA)?
- Waves wash the limestone up into the clouds
- Plates carry it down, the rock heats, and volcanoes vent CO₂
- Winter cold squeezes CO₂ out of the sea-floor rock each year
- Fish eat the limestone and breathe its carbon out
What mainly adds extra CO₂ to the air today, by Noah's reading (NASA)?
- Burning fossil fuels, with some from clearing land
- Growing crops, which give off CO₂ in sunlight
- Volcanoes erupting more often than in the past
- People breathing out more than in the past
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 air back into rock 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 slow cycle into the fast cycle quickly
Rain, rock, river, sea floor, limestone, volcano. Without people, how would carbon in fossil fuels reach the air, by Ren's reading (NASA)?
- Within a year, through plant growth
- Each day, as waves wash it out of rock
- Within a lifespan, as animals breathe
- Slowly, through volcanic activity over millions of years
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 7 billion tons
- About 0.3 billion tons
- About 13 billion tons
- About 3 billion tons
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.
- It depends on water moving from the surface to the depths
- Fish must eat the carbon before it dissolves
- The ocean is already full of carbon and can take in no more of it
- CO₂ cannot dissolve in salt water