Investigating Cellular Respiration Using Carbon Dioxide Data

Help students discover that plants respire day and night — through evidence, not memorization.

This NGSS-aligned worksheet uses a controlled investigation and real numbers to confront one of the most persistent misconceptions in middle school biology: that plants photosynthesize and animals respire, as if the two were opposites.

Students compare carbon dioxide data from two identical sealed chambers — one under a lamp, one in a dark box — then quantify the change, trace where the gas came from, and explain why respiration stays hidden in the light. A misconception check has them select the claim, which they defend in a Claim-Evidence-Reasoning box that requires at least two numbers from the table.

What's included

• Labeled diagram of the two-chamber setup
• 12-hour carbon dioxide data table
• 3 open-response analysis questions, building from quantifying to inferring
• 1 multiple-choice misconception check with targeted distractors
• CER writing frame
• Complete answer key

Skills practiced: reading quantitative data, identifying controlled variables, distinguishing photosynthesis from cellular respiration, and constructing evidence-based explanations.

Great for CER practice, formative assessment, science stations, homework, exit tickets, and review before a test.

No prep. Print and teach. Prints cleanly in black and white.