- Why air moves
- Land and sea breezes
- Global winds
- Jet Streams
- Explain why air moves.
- Identify causes of local winds.
- Describe global winds and jet streams.
global wind: wind that occurs in a belt that circles the planet
jet stream: fast-moving air current high in the troposphere
land breeze: local wind that blows from land to water during the night or in the winter when air over the land is cooler than air over the water
local wind: wind that blows over a limited area because it is influenced by local geography, such as nearness to an ocean
monsoon: local wind that blows from water to land in the summer and from land to water in the winter due to seasonal changes in the temperatures of land and water
sea breeze: local wind that blows from water to land during the day or in the summer when air over the water is cooler than air over the land
wind: air that flows over Earth’s surface because of differences in heating of the atmosphere
Use demonstration #24 (‘Light Bulb Air Current and Wind”) at the URL below to show students how warm air rises and starts a convection current. In the demonstration, you will sprinkle talcum powder over a lamp. Then, when you turn on the lamp, the powder will rise up from the bulb because the bulb is heating the air above it and causing it to rise. State that this vertical movement of air is an air current and that similar air currents form over warm ocean water and the equator. Explain that as the warm air rises, cooler air flows in to take its place. This horizontal movement of air is similar to wind, which is horizontal movement of air over Earth’s surface.
With the instructions and materials at the following URL, students can make a global winds flipbook. Making a flipbook is a great way for students to organize information and prepare for assessments.
Visual learners and verbally challenged students may have a better understanding of land and sea breezes (and other local winds) if they interact with the land and sea breeze animation at this URL: http://oceanservice.noaa.gov/education/pd/oceans_weather_climate/media/sea_and_land_breeze.swf.
Arrange for a few students to interview a local meteorologist about the types of winds experienced in their part of the country. For example, they should ask about the prevailing winds in their area and the types of weather they bring as well as about specific local winds and their causes. Have the students summarize and share what they learn in a brief oral report to the class.
Students can model the Coriolis effect to see how it affects global winds with the activity at the first URL below. Then, with the second URL below, they can apply their knowledge of global winds to complete a global winds map and infer how global wind patterns affected sailing vessels in the past.
Students often think that monsoons always bring heavy rain. Use the monsoon figure in the lesson to point out how the winter monsoon blows from the land to the ocean and is therefore a dry wind. Explain that only the summer monsoon, which blows from the ocean to the land, brings large amounts of rain. You (or your students) can learn more by reading this article: http://employees.oneonta.edu/baumanpr/geosat2/Dry_Monsoon/Dry_Monsoon.htm.
Reinforce and Review
Copy and distribute the lesson worksheets in the CK-12 Earth Science for Middle 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.
Check students’ mastery of the lesson with Lesson 15.4 Quiz in CK-12 Earth Science for Middle School Quizzes and Tests.
Points to Consider
Temperature differences in the atmosphere cause winds. They also cause other weather conditions, such as clouds and rain. How do temperature differences cause clouds to form?
How do temperature differences in the atmosphere affect precipitation?