 A child can learn about water evaporating by seeing it for themselves. You can help them put a small amount of water on a plate and place it outside in the sunlight. Later, they can check the plate and see that the water is gone. You can talk about where the water went. You might say, when the water dried up, it went into the air. That is called evaporation. When the water might go up into the sky and become part of a cloud. This activity helps a child understand evaporation.