Carbon and nitrogen cycling in organisms is the focus of this Grade 7 science investigation, where students trace how atoms move through living systems during digestion, biosynthesis, and cellular respiration. Rather than treating matter as something organisms simply take in or release, students investigate what happens to individual atoms as organisms rearrange them into new molecules and produce waste materials.

Through a matter cycling investigation, students use evidence from real scientific examples to explain why matter is conserved and recycled. The emphasis is on following carbon and nitrogen atoms through biological processes and connecting those movements to the molecules organisms need to function.

🔬 Following Atoms Through Living Systems

Students investigate how matter moves and changes through three important biological processes:

• Digestion: Trace how atoms move as organisms process food.
• Biosynthesis: Explain how organisms rearrange atoms to build new molecules.
• Cellular respiration: Examine how atoms move during the processes organisms use to produce energy.

Students also consider how organisms produce waste materials and use scientific evidence to explain why atoms are not simply created or destroyed when biological processes occur. This provides focused practice in explaining matter conservation and recycling in living organisms.

What Students Do

The investigation uses a station-based structure with recording and wrap-up activities. Students work with station cards to follow the movement of carbon and nitrogen atoms, record information from their investigation, and bring their observations together in a station wrap-up.

These tasks give students opportunities to trace matter through biological processes, explain how atoms are rearranged, and support scientific explanations with evidence. The focus stays on the movement and reuse of matter rather than memorising isolated definitions.

What Is Included

• ✔️ Station cards for the matter cycling investigation.
• ✔️ Student station recording sheet.
• ✔️ Station wrap-up activity.
• ✔️ Answer Key PDF.
• ✔️ Teacher Guide included in the Answer Key PDF, with learning objectives, teaching tips, discussion questions, and common mistakes.

Using the Investigation in Grade 7 Science

Use this resource during a unit on From Molecules to Organisms: Structures and Processes. The station-based format provides a structured way to explore how matter moves through living organisms, while the recording sheet gives students a place to document their investigation. The wrap-up offers an opportunity to revisit the movement of atoms and explain the evidence behind matter conservation.

The included Teacher Guide supports lesson preparation with teaching tips and discussion questions, as well as common mistakes to watch for when students explain digestion, biosynthesis, cellular respiration, and the rearrangement of atoms.

Curriculum reference: NGSS standard MS-LS1-5.

For teachers covering Grade 7 life science, this resource brings carbon and nitrogen atom movement, biological processes, and conservation of matter into one connected investigation, with student materials and teacher support provided together.