Lesson 16.2: Changing
Weather
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Printed: November 24, 2014
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C HAPTER
Chapter 1. Lesson 16.2: Changing Weather
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Lesson 16.2: Changing
Weather
Key Concepts
• Air mass formation and movement
• Types of fronts
Lesson Objectives
• Describe the characteristics of air masses and how they get those characteristics.
• Discuss what happens when air masses meet.
• List the differences between stationary, cold, warm, and occluded fronts.
Lesson Vocabulary
air mass: large body of air with about the same temperature and humidity throughout
cold front: boundary between two air masses in which a cold air mass pushes a warm air mass upward
front: boundary that forms where two air masses with different characteristics meet
occluded front: front that forms when a cold front overtakes a warm front, so a warm air mass is trapped
between two cold air masses
• squall line: line of thunderstorms that forms at the edge of a cold front
• stationary front: boundary between air masses that are stalled in the same place
• warm front: boundary between two air masses in which a warm air mass replaces a cold air mass
•
•
•
•
Teaching Strategies
Introducing the Lesson
Show the class an example of a weather map that shows one or more fronts. The last figure in this FlexBook® lesson
is a good example. Point out the front lines on the map, and ask students if they know what they represent. As
necessary, explain that the lines represent fronts, which are boundaries where large masses of air meet. Tell students
they will learn about air masses and fronts and why they are important when they read this lesson.
Cooperative Learning
Students can work collaboratively to learn about the four different types of fronts. Divide the class into groups of
four students each, and have each student in the group research a different type of front. Students should learn how
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their front forms, the type of weather associated with it, and how it is represented on a weather map. After they
collect the information, have students meet again as a group and share what they learned with group members.
Differentiated Instruction
Pair English language learners and less-proficient readers with other students, and ask partners to make a Venn
diagram comparing and contrasting warm and cold fronts. Have pairs of students exchange and compare Venn
diagrams with other pairs.
Enrichment
Students can learn more about the movement of air masses by investigating how the jet stream is related to the
movement of air masses across North America. Before they start their research, have them use their current
knowledge of weather and the atmosphere to develop a hypothesis for how the jet stream and air mass movement
are related. You could do this step as a class or group brainstorming session. Then have students do online research
to see if their hypothesis is correct. Students should write a summary of what they discover in their investigation.
Science Inquiry
Use the activity at the following URL when students learn about cold and warm fronts. In the activity, they will infer
the location of cold and warm fronts on a map plotted with weather observations.
http://www.srh.noaa.gov/jetstream/synoptic/ll_analyze.htm
Common Misconceptions
A relatively common misconception is that a front is a thin wall of weather. This idea may come from the way fronts
are indicated by lines on weather maps. Point out that the line on a weather map that represents a front shows only
the boundary between two air masses, whereas the weather associated with the front may actually extend over many
miles on either side of the frontal boundary.
Reinforce and Review
Lesson Worksheets
Copy and distribute the lesson worksheets in the CK-12 Earth Science for High School Workbook. Ask students to
complete the worksheets alone or in pairs to reinforce lesson content.
Lesson Review Questions
Have students answer the Review Questions listed at the end of the lesson in the FlexBook® student edition.
Lesson Quiz
Check students’ mastery of the lesson with Lesson 16.2 Quiz in CK-12 Earth Science for High School Quizzes and
Tests.
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Chapter 1. Lesson 16.2: Changing Weather
Points to Consider
How do the various types of fronts lead to different types of weather?
Why are some regions prone to certain types of weather fronts and other regions prone to other types of weather
fronts?
Why does the weather sometimes change so rapidly and sometimes remain very similar for many days?
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