In our experiment, we had one person moving the slinky while the other held it. A third person would time how long it took for the wave to reach the holder and vibrate back to the person that started the movement in the first place. In the videos, notice the wave "bounces" back after reaching the holder.
In this first video, Ben and Alberto demonstrating a P-wave using a Slinky. P-wave stands for primary wave, it is also a compressional wave. Primary waves are the first waves observed during an earthquake. These waves move in a up and down motion (compression), and are followed by S-waves.
Again Ben and Alberto are helping demonstrate for us. This time they are demonstrating S-waves. S-wave stands for secondary wave, these are also called transverse waves. These waves move from side-to-side, in a "S" motion. In our experiment we found that s-waves are the slower of the two and cause the most damage in real-life earthquakes.