Assignment #9 Air Masses
LO: I can model the interaction that occurs during a warm air front
EQ: What is an air mass and which ones affect our weather?
AGENDA 5/18
1.
Notes
2.
Activity
Homework
1.
LEVEL ZERO VOICE
CATALYST (10 minutes, individual work):
What can you determine by the shape of a cloud?
CLASS SHARE OUT
Watch the parts of the video before the water boils and when it boils.
View it from the website OR go to:
https://www.youtube.com/watch?v=SfXi8x9Y3sg
1. How does the air feel above the pan of water before the water boils?
2. How does the air feel above the pan of water when the water boils? Why?
Air Mass
 Body of air with same temperature and humidity
 Form when air stays in one area long enough to take on the
properties of that area (about a week).
 Density of an air mass vary with the temperature and amount of
water vapor
 Warm air masses less dense (lighter) than cold air masses
 Humid air masses less dense than dry air masses
 When air masses with different densities meet, the two masses
do not mix
 Four North American Air Masses
* Most air masses in N. America move west to east

Maritime Polar (mP) – formed over N. Pacific and N. Atlantic Oceans [bring cold and wet
weather]

Continental Polar (cP) – formed over the polar regions over land [bring cold and dry
weather]

Maritime Tropical (mT) –formed over S. Atlantic Ocean and Gulf of Mexico [bring warm and
wet weather]

Continental Tropical (cT) – formed over southwest desert and N. Mexico [bring warm and
dry weather]
Using the image on the right below, label your “North American Air Masses” diagram
and glue under your notes.
Using the image on the right below, label your “North American Air Masses” diagram
and glue under your notes.
PROCESSING TASK Groups of 4
Build a model of two air masses colliding by following the instructions on the board
MODEL OF COLLIDING AIR MASSES
Question: What happens when air masses collide?
Hypothesis: _______________________________________________________
Observations: I noticed _____________________________ when the liquids met
Draw and label your observations.
Leave space to answer questions.
PROCESSING TASK Groups of 4
Build a model of two air masses colliding by following the instructions on the board
MODEL OF COLLIDING AIR MASSES
Question: What happens when air masses collide?
Hypothesis: _______________________________________________________
Observations: I noticed _____________________________ when the liquids met
1. Obtain a cup of blue water.
2. Pour your oil SLOWLY into the water.
3. Observe the movement of the oil in the cup.
PROCESSING TASK Groups of 4
Build a model of two air masses colliding by following the instructions on the board
MODEL OF COLLIDING AIR MASSES
1. Obtain a cup of blue water.
2. Pour your oil SLOWLY into the water.
3. Observe the movement of the oil in the cup.
Questions
1. Describe your first reaction when the liquid met.
2. Draw your observation. Label the liquids and contents.
3. What did you notice happened when the two liquids met?
• Use a sentence starter to answer the question:
• “during the investigation, I noticed…… when the two liquids met” or
• “When the liquids mixed together ______________.”
PROCESSING TASK Groups of 4
Build a model of two air masses colliding by following the instructions on the board
MODEL OF COLLIDING AIR MASSES
Questions
1. Describe your first reaction when the liquid met.
2. Draw your observation. Label the liquids and contents.
3. What did you notice happened when the two liquids met?
• Use a sentence starter to answer the question:
• “during the investigation, I noticed…… when the two liquids met” or
• “When the liquids mixed together ______________.”
4. Which was floating on top? Why do you think they separated?
PROCESSING TASK Groups of 4
Build a model of two air masses colliding by following the instructions on the board
MODEL OF COLLIDING AIR MASSES
Questions
1. Describe your first reaction when the liquid met.
2. Draw your observation. Label the liquids and contents.
3. What did you notice happened when the two liquids met?
• Use a sentence starter to answer the question:
• “during the investigation, I noticed…… when the two liquids met” or
• “When the liquids mixed together ______________.”
4. Which was floating on top? Why do you think they separated?
5. How does density have to do with this?
6. What would happen if the water got heated up?
7. How is this related to when air masses come together?