Seventh-grade science students dove into a hands-on experiment to answer a question posed by their teacher, Carolina Martínez: Can plants obtain parts of their food from the air?
Before beginning, students made evidence-based predictions: would the CO₂ level increase, decrease, or stay the same compared to an open system? Then, using the I² strategy (Identify and Interpret), they recorded three observations (“What I See” or WIS) and three interpretations (“What It Means” or WIM) to better understand what was happening inside this small capsule of plant life.
For the experiment, using a spinach leaf as the primary material, students built a small closed system: they placed the leaf inside a transparent bag with a carbon dioxide (CO₂) sensor, and positioned a grow light about 6–8 inches away to simulate sunlight. Every five seconds, the sensor recorded the concentration of CO₂, allowing the young scientists to observe real-time changes in gas levels.
The results did not disappoint: CO₂ levels dropped, while oxygen and water vapor levels rose. What does this mean? CO₂ entered through the leaf, likely serving as a raw material for photosynthesis, while oxygen and water were released. The students confirmed that, yes—plants can “feed” from the air.
They also compared their experiment with other similar models to strengthen their analysis and scientific understanding. This activity not only encouraged active learning and scientific thinking, but also sparked new curiosity about the natural world that surrounds—and breathes with—us.