Goals
1.  Understand what circulation patterns are where in the world and why.
2.  Understand what the coriolis effect is and how it relates to general circulation.

Resources
Danielson et al.  Earth Science.  Macmillian Publishing Co.:  New York, 1989.

Materials
 

Time
2 Hours

Procedure
1.  Explain that wind moves in curved patterns.  This is due to the coriolis effect. 
2.  Make a diagram on a transparency of an object moving along a straight line on a disc. (The disc is not
    moving).  Have the students make their own diagram as well.  After you are done with your diagram, walk around
    the room to check the students work.
3.  Make another diagram of the disc moving.  The path of the object moves along a curved line (use a different color
    pen).  Same as step 1, have the students make their own diagram, and check their work.
4.  The coriolis effect causes objects to be deflected to the right of their direction of motion in the Northern Hemisphere.
5.  Discuss the movement of air away from a high pressure center; it curves to the right. (clockwise)  In a low pressure
    area, air continues moving right.  (counterclockwise)
6.  Explain how the coriolis effect is important to know in order to understand general circulation.
7.  Discuss how different regions of the world have different climates; likewise, they have different convection cells.
    --temperature differences cause three world size convection cells
8.  Discuss the three regions and label them on the handout using the colored pens.  Each student should have a handout
    to label as well.
      red-doldrums and trade winds
      blue-polar easterlies
      green-prevailing westerlies
9.  Area of historical significance--the doldrums
   Ask students if they know what doldrum means.  According to the dictionary, the word means:  a state or period of
    inactivity, stagnation, or slump.
  --There are two completely different definitions of the word, why?
  --The reason is because of the Atlantic slave trade.  The majority of slaves were transported from West Africa to South
   America.  When slaves were transported from West Africa to North America, the ships had to pass through the equator
   (the doldrums).  Ships have an extremely hard time sailing in the doldrums because there is little wind.  The ship may
   stay still for months.  This is why doldrum has its dual meaning in the English language today.
10.  S.O.S.  What did people do in order to survive if they were stuck in the doldrums?
    --Slave ships were extremely crowded.  There was the risk of:  diseases, sanitary concerns, other health issues
      (dysentery), shortage of food, mentality and morality are lessened
   --What could happen to the slaves?  There was the chance of the following:  slaves may have been thrown overboard,
      the crew may turn to cannibalism, and the above mentioned information
   --slaves were forced to exercise (keep them healthy)
   --the crews of the ships sometimes kept the head of the dad slaves in order to prove what their original count was.

Major Concepts
1.  Science - Weather terminology
2.  Social studies - Atlantic slave trade information

Assessment
1.  Students will turn in their hand outs that they diagrammed
2.  Students will hypothesize where boats sail, based on what they learned from their diagram and the discussion about
    the slave trade.  Criteria for success: understanding of general circulation winds based upon the diagrams and
    the discussion.

Extensions
1.  Have students find where the majority of boats sail today.
2.  Read from a primary source account of a ship's log.  Discuss the methods used for survival.
3.  Do a lab exercise on the coriolis effect.
 

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Submitted By St. Norbert College Ocean Voyagers Program