At the beginning of class show the global picture of the Earth’s wind patterns again (any of the above will do).
Ask students to pay attention to swirling winds in the Westerly
wind belts. What do they notice about the air currents? [The
Westerlies are prone to cyclonic action]. What direction do
the cyclones move? [To the right in the northern hemisphere
and to the left in the southern hemisphere].
2. Using their understanding from the pervious lessons, ask
them to try to explain why the winds move in cyclonic action.
(Don’t be surprised if students have difficulty with
this; the rest of the lesson will make the Coriolis Effect
apparent to them.)
3. After students have made a significant attempt to explain
why the winds are deflected, have them answer the following
question: How is the Earth like a merry-go-round?
4. Allow students a few minutes to answer the question and
to share their responses with the class. Expect “both
spin” to be a top response.
5. Ask students what happens when you toss something to your
friend if you are riding on two different horses on a merry-go-round
right next to each other? [Your friend will have a hard time
catching the ball] From the point of view of either yourself
or your friends, what direction does the ball go (straight
or curved?) [It appears to be thrown behind, in a curve.]
6. Ask students what they think the ball would look from above.
Record students’ answers then show the clip from the
following site: (http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/fw/crls.rxml).
As the students can clearly see from the film clip, the ball
moves in a straight line when viewed from above. The ball only
curves from the point of view of those on the merry-go-round.
7. Ask students to think about wind. How might the ball be
like wind? [Wind blows in a straight line, but is deflected
like the ball].
8. Now take out the turntable, place the circular paper in
the center and slowly spin the turntable. While you are spinning
the table, draw a straight line from the center to the edge.
What do students notice when you take the paper off the turntable.
[The line is curved.]
9. How is this like the earth and winds/clouds? [As the winds
move they appear to be pushed to the side in a curving motion.]
10. Ask students to consider why the winds are not all deflected
11. Ask students to think about being bumped in the hall. When
is the effect more obvious, when they are walking or running?
[Running] Which winds will be more deflected by the Coriolis
Effect? [faster moving winds]
students explain how the spinning of the Earth affects
the apparent motion of the clouds?
Throughout class discussions and in written responses,
students should be able to explain the apparent motion
of clouds as they relate to the Coriolis Force.