Your student sets up two sealed jars side by side: one with a burning tea light releasing carbon dioxide through combustion, and one with an aquatic Elodea plant absorbing that CO2 through photosynthesis. The sheet walks through the full procedure, including a baking soda and vinegar reaction to generate CO2 for the plant jar, then asks students in grades 5-8 to record observations across four prompts comparing what happened in each jar over a 30-to-60-minute window.

The carbon cycle combustion and photosynthesis lab works well as a standalone lesson or as the hands-on anchor for a broader earth science or ecology unit study. By the time your homeschooler fills in the conclusion and Think Further sections, they have articulated how combustion and photosynthesis balance each other in the carbon cycle and begun reasoning about what happens when that balance is disrupted.