Earthquake Lesson Plan
5/26/09 & 5/27/09
Intro
What is an earthquake?
Remember Plate Tectonics – Peeled Orange – Curst of earth is like orange peel and can
move around. Earthquakes happen because of a sudden slip on a fault in the earth’s surface
where the rock on one side moves up, down, or sideways relative to the other side. An
earthquake is felt as a sudden, rapid shaking on the surface of earth. This shaking can last a few
seconds or even a few minutes. The motion causes waves that moves through Earth. Earthquakes
are detected with instruments that measure and record the seismic waves. (On projector show
QCN Live with plate boundaries and earthquakes) – Point out a lot of earthquakes in CA
Who has been in an earthquake?
What do you do during an earthquake?
How do you measure earthquakes?
Activity 1 – Compare Magnitude and Distance with Seismic Waves
Prep
Tape down senor to one end of table
Run QCN Live on computer
Allow kids to play with sensor (Encourage them to jump up and down or bang on the table with
a fist or baseball)
Compare Magnitude and Distance with Seismic Waves (Worksheet)
Drop baseball from different distances and heights.
Ask kids to predict what will happen. Will you get a larger or smaller wave dropping form
high/lower and closer/farther away.
Both the magnitude of the source and the distance from the source influence the amplitude
(intensity of shaking) of the seismogram.
Richter Scale (If Time) – Try to inform them that each number is 10 times stronger
9.0 — Causes complete devastation and large-scale loss of life.
8.0 — Very few buildings stay up. Bridges fall down. Underground pipes burst. Railroad rails
bend. Large rocks move. Smaller objects are tossed into the air. Some objects are swallowed up
by the earth.
7.0 — It is hard to keep your balance. The ground cracks. Roads shake. Weak buildings fall
down. Other buildings are badly damaged.
6.0 — Pictures can fall off walls. Furniture moves. In some buildings, walls may crack.
5.0 — If you are in a car, it may rock. Glasses and dishes may rattle. Windows may break.
4.0 — Buildings shake a little. It feels like a truck is passing by your house.
3.0 — You may notice this quake if you are sitting still, or upstairs in a house. A hanging object,
like a model airplane, may swing.
2.0 — Trees sway. Small ponds ripple. Doors swing slowly. But you can't tell an earthquake is to
blame.
1.0 — Earthquakes this small happen below ground. You can't feel them.
Activity 2 – Slinky Waves and Triangulation – S and P type waves
What is something that has waves?
Can you make different waves with the Slinky?
Do the waves travel at different Speeds?
(P waves move faster than S waves)
Did you know an earthquake is like a wave of water but traveling through the earth!
Slinky Demonstrations of P and S Waves: The P and S waves have distinctive particle motions
and travel at different speeds. P and S waves can be demonstrated effectively with a slinky. For
the P or compressional wave, have two people hold the ends of the slinky about 3-4 meters
apart. One person should cup his or her hand over the end (the last 3-4 coils) of the slinky and,
when the slinky is nearly at rest, hit that hand with the fist of the other hand. The compressional
disturbance that is transmitted to the slinky will propagate along the slinky to the other person.
Note that the motion of each coil is either compressional or extensional with the movement
parallel to the direction of propagation. Because the other person is holding the slinky firmly,
the P wave will reflect at that end and travel back along the slinky. The propagation and
reflection will continue until the wave energy dies out. The propagation of the P wave by the
slinky is illustrated in Figure 5.
Demonstrating the S or Shear wave is performed in a similar fashion except that the person who
creates the shear disturbance does so by moving his or her hand quickly up and then down. This
motion generates a motion of the coils that is perpendicular to the direction of propagation,
which is along the slinky. Note that the particle motion is not only perpendicular to the direction
of motion but also in the vertical plane. One can also produce Shear waves with the slinky in
which the motion is in the horizontal plane by the person creating the source moving his or her
hand quickly left and then right. The propagation of the S wave by the slinky is illustrated in
Figure 6. Notice that, although the motion of the disturbance was purely perpendicular to the
direction of propagation (no motion in the disturbing source was directed along the slinky), the
disturbance still propagates away from the source, along the slinky. The reason for this
phenomenon (a good challenge question for students) is because the material is elastic and the
individual coils are connected (like the individual particles of a solid) and thus transmit their
motion (disturbance or deformation) to the adjacent coils. As this process continues, the shear
disturbance travels along the entire slinky (elastic medium).
Triangulation equals Location using Multiplication – If there is time probably on
Wednesday – after they got that P and S waves move at different speeds
-Try to get across that you need three stations to find a location. Two stations will give you
between two different points
Another thing we could do if time to show difference in wave speed. (Particually for younger
group if there is enough time)
Slow Walk – Walk Activity --An S and P Wave Travel Time Simulation
This is to physically show students different speeds of waves, as they move out from the
epicenter of an earthquake. S wave propagation is simulated by slow walking and P wave
propagation is simulated by walking.