Chapter 12.1 The Causes of Weather pages 314-317

Essential Questions:

1. What is the difference between weather and climate?
2. How do imbalances in the heating of Earth create weather?
3. How do air masses form?
4. What are the 5 types of air masses?

Vocabulary:

1. weather
2. climate
3. air mass
4. source region

Weather vs Climate

Weather = Short-term variations in atmospheric conditions.

Climate = Long-term average of variations in weather for a particular area.

Imbalanced Heating

Two factors affect the temperatures on Earth

1. Tilt of the Earth

2.  Earth is a sphere and light intensity varies at different latitudes due to the angle at which the Sun’s rays strike Earth.  If image is unclear, use this link:  http://www.lpi.usra.edu/education/skytellers/seasons/about.shtml

Areas around Earth maintain about the same average temperature due to these two factors due to constant movement of air and water among Earth’s surface and currents within the oceans.

Weather = from thunderstorms to large scale weather systems is due to this redistribution of Earth’s thermal energy.

Bill Nye Wind Difference in heating produce wind 1:53

mhttps://www.youtube.com/watch?v=uBqohRu2RRk

Bill Nye Wind Full Episode 22:31

mhttps://www.youtube.com/watch?v=zMyBheIn2DA

Air Masses page 316

Air mass = a large volume of air that has the same characteristics such as humidity and temperature as its source region.

The source region is the area over which the air mass forms.

There are 5 types of air masses.  Examine the diagram and complete the table.

Air Mass Modification

Air masses to do stay in one place but rather, travel.  When traveling over land or water that has different characteristics, they acquire those different characteristics.

Check yourself!

Can you answer the Essential Questions for this section?

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