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Lesson and Curriculum
 Lesson
at a Glance:
Curriculum: Activity designed by Keedar Whittle
(download the
lesson plan as an Adobe PDF document)
Grade: Sixth
Topic: Earth’s Interior
Keedar’s lesson featured three activities that illustrate the nature
of the Earth’s mantle. The first used Slinkys® to simulate the
wave movement caused by earthquakes. Keedar has students tie
one end of a slinky to a table or chair leg and then has them simulate
the two types
of waves created at the epicenter of an earthquake. Compression
waves, or primary waves (P waves), are simulated when the students stretch
the
Slinky® out on the floor, and push one end straight toward the other
end. Compression waves are “primary” because they are faster
than shear waves, or secondary waves (S waves). The motion of
a shear wave is simulated by moving one end of the Slinky® back and
forth perpendicular to the other end. In addition to having the students
simulate
both waves, Keedar had them time the waves, to see if they could
detect which is faster.
The other activity involved Silly Putty®, which
has qualities of both a liquid and a solid. Keedar illustrated
this point by having his students
roll the putty into a ball, place it on an index card, and, with
a pencil, trace the outline of the ball. When the students checked
on the putty
30 minutes later, they found that it had spread beyond the outline
they had made, apparently through the force of gravity alone.
Finally, Keedar illustrated convection currents with a specially designed
milky-white colored fluid that shows the currents when
it’s
heated. All three demonstrations provide students with insight
into what is otherwise a wholly inaccessible place — the Earth’s
mantle. The demonstrations, Keedar feels, will leave his students with
a lasting
impression of how the Earth’s interior functions. “Students
may forget certain definitions, and that’s okay. What I would like
is for them to be able to broadly explain plate movements and
interactions down the road. ”
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