1. Lesson Essential Question:
BELLRINGER:
An air mass classified as cT usually forms over which type of Earth surface?
cool water
cool land
warm water
warm land
Lesson Essential Question:
How does the movement of the major types of air masses affect the weather?

2. Today's Activities: Go over bellringer Preview Vocab
Complete the North American Air Masses worksheet
Follow the directions on the front page to develop a map of the different North American Air Masses
Review air masses and how air masses move across the US
Density of Air Demo
Begin homework if time allows

4. Classifying Air Masses
Four major types of air masses influence the weather in North America:
Humidity:
Maritime – wet/humid
Continental - dry
Temperature:
Tropical - warm
Polar - cold 4

5. Types of Air Masses
Air masses can be warm or cold, and humid or dry. As an air mass moves into an area, the weather changes.

6. How Air Masses Move in North America
Prevailing Westerlies
Jet Streams
Fronts

7. Science Challenge Question:7 7

8. The map below shows an air mass that formed over the Gulf of Mexico at location A.
Once air mass A reaches location B, the weather conditions at location B will most likely become
(1) warmer and drier
(2) warmer and more humid
(3) colder and more humid
(4) colder and drier

9. Compared to a maritime tropical air mass, a maritime polar air mass has a
1) higher temperature and more water vapor
2) higher temperature and less water vapor
3) lower temperature and more water vapor
4) lower temperature and less water vapor

10. The graph below shows changes in the atmosphere occurring above typical air-mass source regions A, B, C, and D. Changes in air temperature and altitude are shown as the graphed lines. Changes in water-vapor content, in grams of vapor per kilogram of air, are shown as numbers on each graphed line.
Which list best identifies each air-mass source region?
1) A — cT, B — cP, C — mP, D — mT
2) A — cP, B — mP, C — mT, D — cT
3) A — mP, B — mT, C — cT, D — cP
4) (4) A — mT, B — cT, C — cP, D — mP

11. Science Challenge Question:11 11

12. How do they move across the USA?
Post It Exit:
What are the 4 major types of air masses that affect the weather in North America?
How do they move across the USA? 12