To demonstrate the difference between P-waves and S-waves that occur during earthquakes, you will need the following:
In this demonstration, the plastic slinky represents sediment and the metal slinky represents rock.
- plastic slinky
- metal slinky
1)Two students hold each end of the plastic slinky. One student will be chosen to be the focus/epicenter of the earthquake and the other student will be a town away from the center. The "epicenter" student will take several coils of the slinky and let them go. You will see a "wave" travel down the length of the slinky toward the "town" student and back. Depending on the amount of energy released, it may travel back and forth several times.
2)Repeat with metal slinky. You may want to compare which slinky travels faster.
NOTE: This type is a P-wave or primary wave. It is the first waves that are felt during an earthquake.
3)The students will keep the same position, but this time, the "epicenter" student will snap their end of the slinky up (and really snap it for best results). There should be a hump or "S" shape that occurs in the length of the slinky.
NOTE: This type is a S-wave or secondary wave. It is the wave that causes the ground to buckle or look like waves during an earthquake.
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