About This Lesson
Where Does a Tree's Body Come From? — Photosynthesis Without the Magic Words
Topic: Photosynthesis, attacked through the classic misconception: students think plants "eat soil".
Hook: a 2-ton oak grew from an acorn plus... what? Air is the answer nobody believes — this lesson makes students argue their way to it.
Target learning outcomes — by the end, students can:
- State what a plant actually builds its mass from (CO2 + water, energized by light)
- Explain why a plant in the dark loses mass while one in the light gains it
- Trace the energy: sun → glucose → the student's own breakfast
Audience: Grades 6–8 (ages 11–13), 30 students, mixed ability, a few high-flyers who finish fast and need extension.
School context: Urban middle school, basic science room — no working gas taps, but sinks, windows, and a set of pot plants exist.
Constraints: One 45-minute in-person lesson. The word "photosynthesis" should be earned by the end, not memorized at the start.
