In this FACTivity you will answer the question: How much water is transpired by a tree during daylight hours? Transpiration happens when the water that entered a tree’s roots travels up the tree’s trunk, through its branches, to its leaves, and out of the leaves through small pores. Materials: 1 pint closable plastic bag Permanent marker or small piece of paper, tape, and pencil or pen Graduated cylinder or other measuring device Piece of blank or lined paper and a pencil Topics: Water, Experiment, Group Activity, Tree Transpiration, Water Cycle.