The Water Cycle

The Sun heats the Earth with the electromagnetic radiation it emits. This radiation travels through space and when it gets to Earth it moves the molecules on Earth causing them to heat up. When water is heated it turns to water vapor and rises into the sky (evaporation). As it gets higher, it cools down and condenses into clouds and eventually condenses back into water and falls to the ground as precipitation (rain or snow). This water collects in bodies of water, as snow, or filters into the ground. The cycle then repeats itself.

Experiment

I found his evaporation and condensation demonstration idea on a blog called Lessons for the Little Ones. This is the simplest version of this type of demonstration, especially if the classroom has a very sunny window. The top picture is what the bag looked like after 1 week being in a sunny window. You can see the condensation building up in it. When the droplets are big enough, you can make it “rain” inside the bag. On the blog they put blue food dye in the water. I didn’t do that because I was afraid if the bag fell down that would make a mess. One of the bags I made did fall down so it was good that I didn’t add the food coloring!