Date: May 1994

Grade Level(s): 4, 5, 6, 7, 8, 9, 10, 11, 12

Subject(s):

• Science/Meteorology

Students are somewhat interested in the weather and can be made increasingly aware of cloud formation by this rather simple in class demonstration.

PURPOSE: The purpose to this activity is to demonstrate to the students the direct affects of pressure and temperature on cloud formation.

OBJECTIVES:

1. To demonstrate the principles involved in cloud formation.
2. Transfer this information to weather maps to predict cloud formation and clearing.
3. Introduce the term nuclei, necessary for attachment to form clouds

RESOURCES/MATERIALS:

1. Wide mouth gallon pickle jar
2. Heavy duty clear plastic bag
3. Rubber bands or masking tape

ACTIVITIES AND PROCEDURES:

1. Place about 20 ml of water in a wide mouth gallon pickle jar
2. Place a lit match into the jar.
3. Quickly place a heavy duty clear plastic bag over the mouth of the jar and secure a firm seal by placing a rubber band/masking tape around the top of the jar.
4. Push the bag into the jar quickly, then pull the bag out. Observe!

This activity illustrates how humidity, temperature, and air pressure influence the formation of clouds. The water produces high humidity in the jar and the smoke introduced by the match provides nuclei on which the water vapor can condense. As the bag is pushed into the jar pressure and temperature in the jar increases causing the jar to clear. Upon pulling the bag out, pressure and temperature decrease allowing water vapor to condense and produce a "cloud" inside the jar.

Questions for further inquiry:

1. Why are smoke and water added to the jar? (provide moisture and nuclei for cloud formation)
2. What does pushing and pulling on the bag do to the jar? (increases/decreases pressure)
3. How would warming or cooling the jar effect the observations? (decrease/increase cloud information)
4. Relate your findings to weather conditions necessary to produce cloudy/clear skies.

May 1994

These lesson plans are the result of the work of the teachers who have attended the Columbia Education Center's Summer Workshop. CEC is a consortium of teacher from 14 western states dedicated to improving the quality of education in the rural, western, United States, and particularly the quality of math and science Education. CEC uses Big Sky Telegraph as the hub of their telecommunications network that allows the participating teachers to stay in contact with their trainers and peers that they have met at the Workshops.