We begin with water — the silent mover. I hand each student a pot, a syringe, and a notebook. “Make a wilted plant stand up,” I say. They learn that water isn’t just liquid; it’s tension and cohesion, a highway of hydrogen bonds pulling from root to leaf. One group injects a colored dye into soil and watches xylem vessels paint the stem like stained glass. Another measures transpiration by the tiny drift of a pot’s weight over an hour. We sketch the tension-cohesion chain on the board, but the real lesson arrives when a sunflower leaf, revived, unfolds like proof that physics makes biology possible.
