Air Masses

The Science Center for Teaching, Outreach, and Research on Meteorology (STORM) Project at the University of Northern Iowa and the National Oceanic and Atmospheric Administration.
Type Category
Instructional Materials
Activity , Lesson/Lesson Plan
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be "fully aligned," the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.


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3 Here is an updated link

This is an updated link for the activity maps: And here is a link to a PDF describing the activity:


This is Activity 12 of a set of Level 1 activities designed by the Science Center for Teaching, Outreach, and Research on Meteorology (STORM) Project. The authors suggest that previous activities in the unit be completed before Activity 12: Air Masses, including those that address pressure systems and dew point temperature. In Activity 12, the students learn about the four main types of air masses that affect weather in the United States, their characteristic temperatures, and humidity levels as it relates to dew point temperatures. The lesson plan follows the 5E format. Initially, students discuss local weather and then examine surface temperature and dew point data on maps to determine patterns and possible locations of air masses. They learn about the source regions of air masses and compare their maps to a forecast weather map with fronts and pressure systems drawn in. During the Extension phase, students access current maps with surface and dew point temperatures at and try to identify locations of air masses. They sketch in fronts and compare their results to the fronts map. Evaluation consists of collection of student papers.

Intended Audience

Educational Level
  • Middle School
  • Grade 7
  • Grade 8
  • Grade 6
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

MS-ESS2-5 Collect data to provide evidence for how the motions and complex interactions of air masses results in changes in weather conditions.

Clarification Statement: Emphasis is on how air masses flow from regions of high pressure to low pressure, causing weather (defined by temperature, pressure, humidity, precipitation, and wind) at a fixed location to change over time, and how sudden changes in weather can result when different air masses collide. Emphasis is on how weather can be predicted within probabilistic ranges. Examples of data can be provided to students (such as weather maps, diagrams, and visualizations) or obtained through laboratory experiments (such as with condensation).

Assessment Boundary: Assessment does not include recalling the names of cloud types or weather symbols used on weather maps or the reported diagrams from weather stations.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
The students examine data on weather maps, determine probable boundaries of air masses and compare their weather maps to a forecast map. The teacher will need to elicit evidence for the motions of the air masses and the resulting weather (temperature, humidity, dew point, cloud cover, and precipitation) through further questioning of the students. For example, “What type of weather would be associated with a maritime tropical (mT) air mass?” (rain, high humidity, warm temperatures, etc. ) Or, “What weather could result when an mT air mass meets a continental polar (cP) air mass?” (Thunderstorms, tornadoes). The activity doesn’t address the flow of air from regions of high pressure to low pressure, but if students do Activity 10: Highs and Lows: Patterns in the Wind, it is addressed as are the concepts of barometric pressure and wind.

Science and Engineering Practices

This resource appears to be designed to build towards this science and engineering practice, though the resource developer has not explicitly stated so.

Comments about Including the Science and Engineering Practice
Maps are studied to identify spatial relationships between the location and movement of air masses. Basic statistical techniques of data and error analysis can be added to the lesson through a discussion of forecasting the future movements of the air masses and the probability of errors occurring as a meteorologist attempts to predict future weather patterns. Causation and correlation can be addressed when taking about the relationship between air masses and temperatures and moisture. For example, a correlation exists between a maritime tropical (mT) air mass and warm, moist weather conditions - they may result in warm rains (causation).

Disciplinary Core Ideas

This resource appears to be designed to build towards this disciplinary core idea, though the resource developer has not explicitly stated so.

Comments about Including the Disciplinary Core Idea
The activity addresses the relationship between air masses, their source regions, and resulting weather in terms of temperature and dew point. Previous lessons in the unit address wind, barometric pressure, and precipitation. The complexity of the patterns would need to be addressed as students share their interpretations and discuss varying perspectives. For example, when they are directed to locate and circle areas of low temperature, each may have a different interpretation of what constitutes low temperatures. As described in the Extension, if they monitor air mass movement for a week, they should develop an understanding of the complexity and the unpredictability of weather patterns.

Crosscutting Concepts

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
Cause and effect relationships are examined throughout the activity as students use surface and dew point temperatures to predict the location of weather fronts. When students access the US Station Plots and Fronts link, they can explore the relationship between the location of the fronts and surface and dew point temperatures.

Resource Quality

  • Alignment to the Dimensions of the NGSS: The students examine data to provide evidence for the movement of air masses and the resulting changes in weather conditions. While it doesn’t fit all three dimensions listed above explicitly, it does provide a coherent set of performance expectations and elements of the science and engineering practices, the crosscutting concepts, and the disciplinary core ideas. Several of the science and engineering practices are used briefly – including analyzing data, constructing explanations, and communicating information. In the section “For Further Inquiry,” teachers are directed to challenge students to design an investigation about air masses. The practices could be enhanced throughout the lesson through the use of questioning. For example, instead of the teacher doing the explaining in the “Explain” section, the students could be asked to draw their own conclusions and the teacher could address any misconceptions and questions. The crosscutting concepts, addressed briefly besides cause and effect, include patterns and stability and change. The lesson is part of a larger set of lessons all related to weather.

  • Instructional Supports: The lesson provides an authentic, meaningful investigation of air masses affecting weather in the United States in a scenario that reflects the interconnected nature of science as it is practiced in the real world. The material is presented in a scientifically accurate manner at a level appropriate for middle school students. They analyze patterns in the temperatures found on the maps and construct an explanation based on evidence to support their thinking. The activity doesn’t mention student collaboration, but students could compare their maps with other students. Teachers should provide opportunities for students to express, clarify, and justify their ideas and respond to teacher’s and peers’ feedback. Connections can be made to local weather patterns. The teachers should provide alternative methods for justifying results for students struggling to meet performance expectations. Extension activities could include the relationship of air masses to major weather events such as blizzards and hurricanes. The total time needed for the lesson and the required materials were noted.

  • Monitoring Student Progress: The Evaluation portion of the activity mentions teacher observation of students’ predictions and results and that teachers should collect student work. To monitor student progress, the teacher will need to ask students to respond to questions such as, “Describe the relationship between the temperatures and location of fronts.” By accessing the activity website on different dates, other map sets are available that could be used as an assessment tool. The lesson needs an assessment of student proficiency, so the teacher should build in formative assessment with a rubric or scoring guidelines. Students should collaborate with one another and communicate their analysis of the data using multiple representations.

  • Quality of Technological Interactivity: Links to current weather maps are provided.