Here is my favorite water cycle experiment.
Before the experiment，teach your students about the water cycle and the following words：evaporation，condensation，precipitation and collection.
Water on Earth keeps going around in the water cycle. When the sun heats the water，some of it turns to a gas （water vapour）. This is evaporation. Then this water vapour rises into the air.
When the water vapour meets the cold air in the sky， it turns back to water drops and collects in clouds. This is condensation.
When too many water drops form in a cloud，the cloud gets heavy and the water falls back to the earth as rain or snow. This is precipitation.
When the water falls back to the earth，it may fall back in the rivers，lakes，oceans or on the land. This is collection. When the sun heats the water，the cycle begins all over again.
This science experiment will help show the water cycle.
●Put a small cup in the center of a large bowl.
●Fill the bowl with water about 2/3 of the way up the cup （do not put water inside the cup）.
●Cover the bowl with a plastic（塑料的） bag and tie it.
●Put it outside in a sunny area for a few hours.
After several hours，the plastic bag will have water drops on it and some of the water will have dropped into the cup.
This experiment shows the heat of the sun turning the water in the bowl to vapour. The vapour turns back to water drops on the plastic bag. Drops get too heavy and fall back down to the water in the bowl or in the cup just like mountains or land on Earth.
After the experiment，check students' understanding of the water cycle by asking them to draw a map of the journey of the water in the experiment.
