Outreach 2014

 

CANDAC Outreach

Title: Clouds in a Jar

Grade Level: Secondary

Subject: Science and Technology

Duration and frequency of activity: 20-30 minutes

 

Lesson at a glance

Students investigate how pressure and pollution in the atmosphere are linked to the formation of clouds by making a cloud chamber.

Focus question(s)

What is needed for clouds to form? How can you create your own cloud in a jar?

Background

Three things are necessary for clouds in the atmosphere to form:

· Moisture - There must be sufficient water vapor in the air for a cloud to form.

· Cooling air - The air temperature must decrease enough for water vapor to condense.

· Condensation nuclei - Tiny particles such as dust, dirt, aerosols, and pollutants are needed to provide surfaces on which water molecules can gather and condense into water droplets.

When you pull the glove out of the jar, the air pressure is lowered inside the jar. The jar contains the same number of air molecules, but they have more space between them (they are less dense). Molecules collide with each other less frequently and slow down, causing the air temperature to go down. When you press the rubber glove into the jar, you are increasing the air pressure. The air becomes denser as the molecules are crowded together. This also causes the air to heat up as molecules collide with each other more often. The smoke particles provide tiny nuclei on which water vapor molecules condense, when the air temperature cools. This forms a little cloud.

Instructions


 

1. Fill the bottom of the jar with water.

2. Hang the glove inside the jar with its fingers pointing down, and stretch the glove's open end over the mouth of the jar to seal it.

3. Insert your hand into the glove and quickly pull it outward without disturbing the jar's seal. Make observations.

4. Next, remove the glove, drop a lit match into the jar, and replace the glove.

5. Pull outward on the glove once more. Make observations.

6. Change one or more of the variables (e.g. temperature of the water, number of matches, etc.) in the experiment and make observations.

Materials

· jar

· latex glove

· matches

· water

Instructional method

· Discussion

· Oral questioning

· Experimentation

Assessment

Demonstrates an understanding of cloud formation.

Ability to form a cloud in a jar.

Helpful links

· Students can learn about different cloud types using the Environment Canada cloud chart found at http://www.ec.gc.ca/Publications/643BB615-17E8-4952-B73A-E21373F0B22B/cloud_poster_e.pdf.

CANDAC research connections

· The atmosphere is made up of tiny molecules of gas and small suspended particles called aerosols. Aerosols can be solid or liquid particles ranging in size from a fraction of a micrometer to a few hundred micrometers. They originate from a variety of natural and anthropogenic sources. Some examples include volcanoes, bacteria, sea spray, pollen, dust, various pollutants and tiny droplets of water. Aerosols affect our weather and climate because they change the amount of sunlight reaching Earth’s surface. Aerosols provide nucleation sites for cloud droplets to form. A cloud with high aerosol concentration will have more, small droplets. Different sized droplets fall through the atmosphere at different rates, which means that changing aerosols in the atmosphere can change the frequency of cloud occurrence, cloud thickness, and rainfall amounts.

· Photocopy each student a copy of the article titled, “Occurrence of weak, sub-micron, tropospheric aerosol event at High Arctic latitudes” and read through the article together as a class. Begin by reading the title and asking students what they think the article might discuss. Then read the abstract, introduction and conclusion sections and asks students to paraphrase each section. Assign pairs of students to examine and interpret Figure 1, 2 or 3. Discuss each figure as a class before reading the remainder of the article. Read the article as a class, stopping to ask questions and summarize important points throughout the article. It may be useful to have a student record important points on a piece of chart paper or in their notebook so that notes can be photocopies and shared later.

· Ideas of questions to ask students:

1. What is a direct effect of aerosols on climate?

2. What are some indirect effects of aerosols on climate?

3. What type of aerosol was the plume?

4. Where did the plume originate?

5. How long does it take for the aerosol plume to travel from its source to Eureka?

6. What type of instruments were used to measure the plumes?

Extension/adaptations

· For advanced students, simply give them the materials and tell them to create a cloud. Ask students to write an experimental procedure to produce the most prominent cloud.

· Have students determine the cloud type of their cloud in the jar.

Source

· Web Weather for Kids: “Create a Portable Cloud!” University Corporation for Atmospheric Research retrieved on April 18, 2011 from <http://eo.ucar.edu/webweather/cloudact1.html>.