How to Create an Interactive Lesson on the Water Cycle

Though the water cycle is a relatively simple concept to grasp in the abstract, it's much easier for students to understand the entire process when they can visualize it. You can create an interactive lesson about all the components of the water cycle. With just a few simple materials, student can see evaporation, condensation and precipitation as it happens.

Difficulty: Moderate

Instructions

Things You'll Need:

• Implement to boil water
• Container for boiling water
• Container with a handle
• Ice cubes
• Pie pan

Conduct a Evaporation Activity

1. Open a class discussion about where the water goes when a puddle dries up or when you hang clothing to dry. Ask students whether the water disappears faster in hot weather or in cold weather.

2. Tell your students that you will create a simulated puddle to discover where the water goes. Pair up the students and give each pair two dishes.

3. Have each pair put a spoonful of water in each dish, leaving one in direct sunlight (or under a bright lamp) and the other in a shady place. Ask the students to write down predictions of what they think will happen if the dishes are left overnight.

4. Check the dishes in the morning and have students record what they see. Ask them to hypothesize what happened to the water and why one dish has more water left in it.

5. Explain to the students that they have witnessed the first part of the water cycle,known as evaporation. Talk about the process of evaporation and ask for other examples of this process.

Conduct a Condensation Activity

6. Review the concept of evaporation with your students. Ask them predict the next step in the water cycle. Guide them toward thinking about where the water goes after it evaporates.

7. Pose questions about air temperature and clouds to the class. Ask them to think about what happens to both warm and cold air and how clouds are formed. Eventually you would like the students to name the three things that are necessary to form clouds: cooling air, water vapor and condensation particles.

8. Provide each group of students with some tape, a 2-liter bottle with a cap and a temperature strip. Ask them to tape the strip in the bottle, put the cap on and place the bottle on its side so that the strip can be easily read.

9. Take a baseline temperature of the bottle and then squeeze the bottle with both hands for approximately 1 minute. Record the temperature and let the bottle sit for another minute before recording the temperature a third time. Note the fact that the temperature changed when the bottle was squeezed and then again a minute later.

10. Open the bottle and use an eyedropper or spoon to put a few drops of water inside. Re-cap the bottle and rotate the bottle so that the water coats the inside of the bottle. Squeeze the bottle once more and not the temperature.

11. Place the bottle on its side and take off the cover. Smush the bottle to let out about half the air. Light a match, blow it out and put the smoldering match in the bottle. Let the bottle quickly reinflate and put the cap back on. Squeeze the bottle for 1 minute and when you let go, you should see a cloud.

12. Explain that the cloud was formed as the air pressure and temperature increased when you squeezed the bottle. As the water evaporated, it became water vapor, which condensed into a cloud when the temperature dropped again.

Conduct a Precipitation Activity

13. Review the concepts of evaporation and condensation with your students and then ask them to tell you the next part of the water cycle. Give them hints if necessary, by wondering aloud about how rain, snow and hail come to be.

14. Boil a pot of water in an open space where all the students can see what's happening. As the water boils, fill the container with a handle with ice.

15. Hold the container of ice over the steam from the boiling water and put the pie pan on the table directly underneath the ice-filled container. Ask the students to watch carefully as the steam affects the container of ice. They should see water dripping from the bottom or at least hear it hit the metal pie pan.

16. Discuss with the students what they saw happening. Let them know that the big drops that condensed on the side of the container represented a cloud. When the drops began to collide with each other, as they do when wind blows in a cloud, they form larger drops that eventually become too large to stay in the sky. This creates rain or (depending on the air temperature) another form of precipitation.

[JMOrganizations]

on 2/13/2008 Thank you for the great information.