I study the process by which water returns from the surface of the Earth to the atmosphere in the form of vapor. This process is called evapotranspiration. Without it, water would not cycle around the globe! It includes the evaporation of water from all surfaces, for example, a lake, ocean, or the top of the soil. It also includes transpiration, which is the process by which plants return the water they take from the soil to the atmosphere through tiny pores in their leaves. Because water vapor is a gas, it is harder to measure it compared to water in its liquid form. For example, if you...