Carbon and Nitrogen Cycles for Kids: How Matter Moves (Grade 8 Science)

Hi, I'm Luna from DoodleBeez. The atoms in your body have been recycled for billions of years. Carbon and nitrogen move between living things, air and soil in endless loops called cycles.

Carbon is in every living thing. Plants take in carbon dioxide from the air during photosynthesis. They use sunlight to turn it into sugar. Now the carbon is part of the plant.

Animals get carbon by eating plants or other animals. Both plants and animals release carbon dioxide back into the air when they use food for energy. This is called cellular respiration.

When living things die, decomposers like fungi and bacteria break them down and release carbon. Some ancient remains became coal, oil and gas. Burning these fossil fuels puts that stored carbon into the air.

Nitrogen makes up about seventy eight percent of air. Living things need it to build proteins, but most cannot use nitrogen gas directly. Special bacteria in soil and in plant roots change it into a usable form.

Plants take up the usable nitrogen through their roots. Animals get it by eating plants. When they die, decomposers return the nitrogen to the soil, and other bacteria release some back into the air.

Now it's your turn. Which process moves carbon from the air into plants, photosynthesis or respiration? Pause and try. Photosynthesis takes in carbon dioxide. Respiration releases it.

Great job! Remember, carbon cycles through photosynthesis, respiration and decomposers. Nitrogen cycles with the help of bacteria, plants and decomposers. Practice the carbon and nitrogen cycles in the Science Lab at doodlebeez.com. See you next time!