The Water (Hydrologic) Cycle: Transpiration

In this lab, learners grow broad bean (also called fava bean) plants in three EarthBoxes for a few weeks before exposing one to wind (using a fan), another to heat (using a lamp), and the third to nothing (the control). The experiment investigates how different conditions affect the rate of transpiration, defined as the loss of water through the small openings of the plant leaves called stomata. It takes around 17 days to grow the plants, and the experiment itself requires 4-5 days. Included worksheets ask learners to make predictions, collect and graph data, draw their observations, and analyze their data. [Activity is publicly available through a web crawler capture on Archive.org.]