NORTHWEST WEATHER WATCH

Experiment #2: Create a Cloud

In our last Experiment we discovered that there is moisture in the air called water vapor and that when the air is cooled the water vapor condenses (changes from gas to liquid) onto a surface. (the jar)

These 2 factors - water vapor & cooling air must be present in order for a cloud to form. But there is one more factor that must also be present. In this next experiment, your group will try to find the missing "mystery" ingredient.

Question: What is the third factor which must be present in order for a cloud to form?

To complete this Experiment your group will need to fill out 2 Lab Sheets. (You will be doing the same experiment two times, but using 1 more step the second time around.) You will record the 2 different procedures on 2 different Lab Sheets.

You can fill out this Lab Sheet on the computer and send it to your teacher's email address by clicking on the submit button when you are finished. Or click on this version, print it out, and fill in the Experiment # 2-A and the Question on your Lab Sheet.

Now you're ready to begin the Activity

You will need:

Discuss the question with your group and come up with a hypothesis. Record your hypothesis on your Lab Sheet. (2-A)
  1. Fill the jar with hot water.
  2. Pour out most of the hot water leaving about 2 cm of water in the bottom of the jar.
  3. Prop the black construction paper so that it stands up behind the jar.
  4. Turn the lid of the jar upside-down and fill it with ice.
  5. Then place the lid filled with ice upside-down on top of the jar.
  6. Let the jar sit this way for at least 10 minutes.
  7. Now, shine the flashlight on the jar.
    • What do you see?
  8. When you have finished this procedure, record steps 1-5 on your Lab Page. (2-A)
  9. Next record your observations on the Lab Page. (2-A)
    • Did you create a cloud?
Now you will do the Experiment again - adding one more step.

You can fill out this Lab Sheet on the computer and send it to your teacher's email address by clicking on the submit button when you are finished. Or click on this version, print it out, and fill in the Experiment # 2-B and the Question on your Lab Sheet.

  1. Fill the jar with hot water.
  2. Pour out most of the hot water leaving about 2 cm of water in the bottom of the jar.
  3. Turn the lid of the jar upside down and fill it with ice, but do not put it on top of the jar yet. Have it ready to place on top of the jar as soon as you complete step 4.

    Put on your safety goggles!

  4. Strike a match and drop the burning match into the jar.
  5. Immediately cover the jar with the lid filled with ice as in the first experiment.
    • What do you see?
  6. Record step #4 of Experiment 2-B on your Lab Sheet.
  7. Next record your observations on the Lab Sheet. (2-B)
    • Did you create a cloud?
    • Do you still have the same hypothesis after seeing the results of your experiment?
  8. Fill in Hypothesis Revisited on your Lab Sheet. (2-B)
  9. Following the class discussion write your Concluding Hypothesis on your Lab Sheet. (2-B)
  10. When your group has finished completing both Lab Sheets (Experiment 2-A and Experiment 2-B), turn in your Lab Sheets and return to your seat.
  11. Write a definition in your Science Journal for the term:
    • suspended particles
      (Scientists call these condensation nuclei.)

[Live from Earth & Mars]__________________________________________________