Place the poster board near a window that receives direct sunlight for at least part of the day. Observe the inside of the top cup every half-hour for a period of three or more hours. The water vapor lost by the leaves through transpiration is collected in the plastic cup on top of the poster board. More droplets appear on the side of the cup facing away from the window because the plastic cup is cooler on this side. Every day, a large tree loses enough water for you to take eight long showers.
Plants absorb water from the soil through their roots.
This loss of water from leaves by evaporation is called transpiration. Other plant processes that involve water include photosynthesis, which uses water to make food, and respiration, in which water is produced. Don't miss Janice VanCleave's new book Science Around the Year .