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When we burn fuel, where does the carbon go? And how much of it stays in the air?
Carbon Cycle lab · Last updated: 16 October 2026
When we burn fuel, where does the carbon go? In this 3D lab, you follow carbon atoms as they move between the air, plants, animals, oceans and rocks, and see how much of it stays in the air. It connects everyday energy use to the carbon dioxide that is warming our planet.
What you'll discover
- Carbon moves between the air, living things, the oceans and rocks in a continuous cycle.
- Photosynthesis takes carbon dioxide out of the air, while respiration, decay and burning put it back.
- Burning fossil fuels adds carbon faster than oceans and plants can absorb it, so the level in the air rises.
The science in plain words
Carbon is in every living thing, and it is constantly on the move. Plants and algae take carbon dioxide from the air and use photosynthesis to build it into sugars. Animals eat plants and use that carbon in their own bodies. Through respiration, all living things return carbon dioxide to the air, and when they die, decomposers release more as they break the remains down.
Some carbon is locked away for a very long time. Over millions of years, buried plants and tiny sea creatures became coal, oil and natural gas, and shells became limestone. The oceans also hold a vast amount of dissolved carbon. Normally these slow stores change very gradually.
Burning fossil fuels releases that ancient carbon in a few lifetimes instead of millions of years. Only part of it stays in the air: the oceans and land plants absorb a large share, and roughly half of what we emit remains in the atmosphere. Even so, carbon dioxide has risen from about 280 parts per million before the Industrial Revolution to more than 420 today. Because carbon dioxide traps heat, this rise is warming the planet. The carbon soaking into the sea also makes it more acidic, which harms corals and shellfish.
Where it fits
- India, NCERT: The full carbon cycle goes beyond the NCERT syllabus for classes 6 to 10; it builds on photosynthesis and respiration in Class 10 Life Processes.
- United States: Grades 6 to 12
- Next Generation Science Standards: MS-ESS3-5, HS-LS2-5, HS-ESS2-6
Common questions
What is the carbon cycle?
The carbon cycle is the way carbon moves between the air, living things, the oceans, soil and rocks. Plants take carbon dioxide from the air, animals eat plants, and respiration, decay and burning return carbon dioxide to the air, where the cycle begins again.
Where does carbon dioxide from burning fuel go?
Roughly half stays in the atmosphere, where it traps heat. Most of the rest is absorbed by the oceans and by land plants and soils. The share taken up by the oceans dissolves in seawater and makes it slightly more acidic.
How do trees help reduce carbon dioxide?
Trees take in carbon dioxide during photosynthesis and store the carbon in their wood, roots and leaves for as long as they live. Forests therefore act as carbon stores. If trees are cut down and burned or left to rot, much of that carbon returns to the air.
Related labs
- Greenhouse Effect: How does a little CO₂ in the air keep the whole planet warmer?
- Photosynthesis: Plants make their food from light, water and carbon dioxide. Can we see it happening?
- Combustion: Put a jar over a candle. Why does the flame go out, and when?
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Try it yourself
The Carbon Cycle lab is one of the interactive 3D science labs inside Taz. Change one thing, predict what will happen, then run it and watch. Labs open after you sign in.