Miss Green says to her class, "Please draw a picture of water." Sam draws a picture of a river. Emily draws a picture of cloud. Mathew draws a picture of falling snow. Shelly draws a picture of ice cubes(块).
Miss Green looks at all the pictures and smiles, "These are all pictures of water. Let's find something more."
Water is found in three forms (形状). It can be gas, liquid(液体) or solid (固体).Heat causes water to change from liquid into gas. When water is gas, it's called water vapor (水汽). Steam (蒸汽) is a kind of water vapor. There is water vapor in the air.
Liquid water is the water that flows (流动) in rivers. We swim in liquid water. We also drink liquid water. The liquid water fills the oceans.
Water tums solid when it's below 0℃. Ice and snow are two kinds of solid water. Some clouds are also made of tiny (极小的) drops of ice and some are made of tiny drops of water.