1. Day 46 Investigation 9 part 1 Air Masses

2. Earth’s Weather Earth’s weather happen where? Troposphere

4. Stagnant Air An air mass that stays over a portion of Earth’s surface for a long time and doesn’t move Can form over any part of the Earth – Usually forms over areas with uniform surfaces with few mountains – Called source regions Stagnant air changes, depending upon the type of surface below the air

6. North American Air Masses Location B (northern Canada) Characteristics of the Air? – Cold – Dry

7. North American Air Masses Location D (Gulf of Mexico) Characteristics of the Air? – Warm – Humid

8. North American Air Masses Meteorologists use a code when making notes about the air masses Combine the names of air masses – Continental (c) - land – Maritime (m) - ocean or sea – Polar (P) - near the poles – Tropical (T) - tropical

9. North American Air Masses Location B – Located over Canada – Continental polar air mass Continental Polar – Air mass that forms over cold land Location D – Located in the Gulf of Mexico – Maritime tropical air mass Maritime Tropical – Air mass that forms over warm water Maritime - anything to do with oceans or seas

10. North American Air Masses Determine the air mass code for each air mass Don’t forget: Lower case term will go first !!!!

11. North American Air Masses mP cP mP cT mT

12. Air Masses Formation No Air Masses are formed here Air is moving Does not stagnate Does not pick up the characteristics from the surface below

13. Air Masses Formation Coldest air masses form here in the winter Warmest air masses form here in the summer Called the Horse Latitudes

14. Balloon Demo. Let’s take the large plastic bag outside to see if we can create an air mass. How might we accomplish this?

15. Solar Balloon Demonstration Take page 55 of of your lab book. Answer questions 1-4 after the demonstration.

16. Solar Balloon Discussion Why is the bag starting to float? What is happening to the temperature and density of the air inside the bag? What is happening to the plastic bag itself? Describe any changes you observe.