As a way to combine life and physical science, or simply as an investigation of plant transpiration, this lesson is sure to inspire! Middle schoolers capture the moisture given off by plants that are placed in different conditions. They relate the output to the surface area of the leaves. Finally, and here is the connection, they hypothesize how what they learned might apply to the size of a photovoltaic cell and its energy output. This terrific resource provides everything you need for a valuable classroom experience.