This project is an easy and inexpensive way to show students how the water cycle works. Each student needs a sandwich bag. Students can draw the water cycle on their bags with a permanent marker and write their names. Bring a bucket of water and a measuring cup to class and have each student fill a small paper cup with three ounces of water. Students will put the cup in the bag and seal it tight. Tape the bags to windows inside your classroom, and have students observe the bags in the morning and afternoon. Students will see condensation on the bags in the morning and will see evaporation in the afternoon. Water will evaporate from the cup and drip down into the bag.
This project is meant to teach third-graders about evaporation and allow them to see it in action. Students need two dishes. They will put two teaspoons of water on each dish. Place one dish outside when the sun is shining and leave one dish indoors. Observe both dishes every four hours. When the sun has set, take the outside dish inside and compare the dishes. The dish left outside will have little to no water left because of evaporation.
This science project will allow third-graders to actually create a cloud. A parent or teacher should assist the child while this experiment takes place. To start the project, tape a temperature strip inside an empty, clear, plastic two liter bottle so that you can read the temperature. Temperature strips are available at pet stores. Seal the bottle tightly with the cap. Read and record the temperature inside the bottle. Use both hands to squeeze the bottle together as hard as you can and read and record the temperature. Notice that pressure creates a higher temperature. Now put a few drops of water in the bottle and roll the drops around to dampen it. Lay the bottle on its side and open it. Push down on the bottle to temporarily crush it to about half its size. Have a parent or teacher light a match, blow it out and throw it into the bottle while it's still smoking, and quickly release the sides of the bottle and tighten the cap. Water molecules should have condensed into a cloud.
A parent or teacher will need to assist the third-grader for this project. The parent or teacher will be boiling a pot of water. He then will hold a bowl of ice over the steam and use a pie tin to collect water runoff from the bowl. Have third-graders observe this process because this is similar to what is going on in the atmosphere. The misty droplets condensing on the side of the bowl represent clouds and when the droplets get larger and heavier and the water drips off of the bowl it represents rain.