How does nitrogen get from the air into living things?

Nitrogen-fixing bacteria and lightning turn nitrogen gas into forms that plants can take up through their roots. Animals get nitrogen by eating plants, and decomposers return it to the soil. Label the Nitrogen Cycle in a Prairie maps these steps.

A tracer is a form of an atom that acts the same in reactions but can be told apart, such as oxygen-18, which is slightly heavier than oxygen-16. A machine that sorts atoms by mass shows where it ends up. That lets scientists follow atoms through a reaction.

8th Grade Food Webs and Matter Cycles Worksheets

Ages 13-14 · Free previews · Print-ready PDFs

Written by Adi Ackerman, Head Teacher

Matter cycles through an ecosystem as living things take in, change and release atoms such as oxygen and nitrogen. There are 2 sheets for 8th grade here, each with an answer key. Tracer Experiments Reveal Photosynthesis Atoms follows oxygen-18 in the 1941 algae experiments, and Label the Nitrogen Cycle in a Prairie traces one nitrogen atom through nine arrows. The sheets practice MS-LS1-6 and MS-LS2-3.

8th Grade Science Ecosystems Food webs and matter cycles Clear All

Label the Nitrogen Cycle in a Prairie

Grade8th Grade

TopicEcosystems

Tracer Experiments Reveal Photosynthesis Atoms

Grade8th Grade

TopicEcosystems

More ecosystems worksheets

Explore all of our 8th grade ecosystems worksheets, covering populations and invasive species, food webs and matter cycles, symbiosis and predators, biomes and biodiversity.

Populations and invasive species Symbiosis and predators Biomes and biodiversity

Frequently Asked Questions

It comes from water. In 1941, Samuel Ruben, Martin Kamen and coworkers gave algae water or carbon dioxide marked with oxygen-18 and tested the oxygen gas. The tracer sheet has students compare the two setups.

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