This lesson is based on a module developed by the University of Illinois WW2010 project. It introduces air masses that commonly influence the weather in the United States, characteristics of these air masses, and how to identify air masses on weather maps.
Once you have had a chance to go through the Air Masses Scaffolding Activity, you should go online to check your answers about the key air mass characteristics. To do this, go to Air Mass #1 and Air Mass #2 to check your answers. Be sure to take notes as you proceed. You will discuss your answers with your class.
Now, you should go to and read the information and directions for activity #2. Follow the deeper pages into the site so you can learn about reading temperatures, surface observations, and the example to see how to find and draw an outline of the air masses.
Before you map out the tropical and polar air masses using temperature, you will need to understand how to read the symbols on the Interpreting Surface Observation Symbols page. It is recommended that you go through the deeper pages covering Temperature, Weather Symbol, Dew Point Temperature, Cloud Cover, Sea Level Pressure, and Wind Barb with your class.
Now, you should go to and read the directions and information for activity #3. Once again, go through the deeper site pages with your class, particularly the ones for tropical air mass and polar air mass, which offer sample map graphic outlines that take into account the surface observations or "additional information."
This esheet is a part of the Air Masses lesson.