Effect of Air Temperatures
on Pollutants
Rebecca Pittman, Educator, Mathematics & Science Center
Developed with funding from the Mathematics & Science Center as part of the
course, Air Quality for Sixth Grade Teachers, Summer 2003
Curriculum
Grade 6, Earth Science, Environmental Science
Key Concepts
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Air temperature can play an important role in the buildup or dispersal of
surface air pollution.
Air close to the earth absorbs surface heat and begins to rise. Winds are
caused by cool air rushing in to take the place of the rising warm air. This
cyclic movement of air is called convection currents.
Air temperature normally decreases with altitude. A temperature inversion
occurs when a mass of warm air moves over stagnant, cooler surface air
forming a lid over the area.
Overview
This modeling activity illustrates convection currents and a cold weather
temperature inversion.
Materials
Each station will need:
 2 identical small jars*
 cardboard square or index card*
 hot mits
 500 mL beaker
 hot and cold water
 food coloring
 safety goggles
 plastic pan
Safety
Follow normal classroom safety rules. Be especially careful when handling glass
jars.
Time
50 minute lab block
Grouping
Student teams of 2 or 3 work well for this activity.
Procedure
1. Place one small jar into the plastic pan. Carefully fill this jar to the brim
with hot water. Add a few drops of food coloring to represent pollution in
the air.
2. Fill the other small jar with cold water. Place the square of cardboard over
the mouth of this jar.
3. Hold the cardboard in place and flip the cold water jar over the top of the
hot water jar. Match the openings of both jars exactly.
“Effect of Air Temperatures on Pollutants”
http://mathinscience.info/
© Mathematics & Science Center 2005
4. Slowly remove the cardboard from between the openings of the two jars.
The jar openings must remain exactly matched during this process.
5. Record your observations.
6. Repeat the experiment but this time add food coloring to the cold water. Put
the cardboard over the mouth of the jar containing the hot water. Using hot
mitts to protect your hands invert the jar of hot water over the cold water.
7. Remove the cardboard and record your observations.
Assessment
Observations for step 5:
What happens to the pollution?
Observations for step 7:
What happens to the pollution?
1. The different temperature waters in your experiment simulated the behavior
of warm and cool air masses. Is warm air or cool air denser? Explain based
on your observations.
2. Based on your lab activity, label each diagram below as an example of
either a temperature inversion or convection current. Identify the air in each
jar as cold or warm air.
“Effect of Air Temperatures on Pollutants”
http://mathinscience.info/
© Mathematics & Science Center 2005
3. Which condition, the presence of convection currents or a cold weather
temperature inversion, trapped pollutants on the surface of the Earth?
4. How would the trapping of pollutants on Earth’s surface affect air quality
over a city?
Danger In The Air!
Resources/Extensions http://wwwk12.atmos.washington.edu/k12/pilot/danger_in_air/teacherpage_tempinv.html
Temperature inversion demonstration and explanation.
Picture of a Temperature Inversion
http://epod.usra.edu/archive/epodviewer.php3?oid=93152
Photograph and discussion of the formation of temperature inversions in
mountain valleys.
Thunderstorms & Tornadoes
http://www.ucar.edu/educ_outreach/webweather/tornact2.html Activity and
discussion of the role of convection currents in the development of
thunderstorms and tornadoes.
*Teacher Note:
Advance Preparation
Collect 2 identical small jars for each student group or activity station.
Use index cards or cut cardboard into squares that when placed over the mouth
of the jars will extend approximately 1 inch beyond the edges.
Ice water and water from the hot water faucet at your sink should work fine for
this activity. When the cold water is placed on top of the warm water the hot and
cold water immediately mix. The pollution in the lower jar is diluted as the
warm water carries some of the red food coloring up into the cooler water. When
the warm water is placed on top, the colder water and the pollution are trapped
and cannot move upward. Dilution and dispersion do not occur.
“Effect of Air Temperatures on Pollutants”
http://mathinscience.info/
© Mathematics & Science Center 2005