Seismic Slinky: Modeling P and S waves


How do seismic waves interact and move through the Earth?

Explore the characteristics of different types of seismic waves with a Slinky©! Explore seismic wave concepts and how they relate to real world situations. Earthquake early warning depends on the difference between the faster P wave and the slower S wave. The goal is for people to receive alerts before damaging shaking from the S-wave arrives. If you feel shaking or receive an alert, take a protective action such as 'Drop, Cover, and Hold On'.


Learners will be able to:

  • Use the model as a tool to observe and understand seismic wave properties.
  • Describe the difference between P and S waves based on the direction of particle motion relative to the direction of propagation.
  • Understand that seismograms show characteristics of each type of seismic wave.

Related Videos

A video demonstration of how a slinky can be a good model for illustrating P & S seismic waves movement.

Video Novice

Related Animations

We use exaggerated motion of a building (seismic station) to show how the ground moves during an earthquake, and why it is important to measure seismic waves using 3 components: vertical, N-S, and E-W. Before showing an actual distant earthquake, we break down the three axes of movement to clarify the 3 seismograms. 

Animation Novice

An earthquake or explosion can generate seismic waves. These elastic waves may travel either through the earth’s interior as "body waves" (P and S waves) or along or near the earth’s surface as "surface waves" (Rayleigh and Love waves). This set of four animations shows the behavior of each using a 3-D grid.

Animation Novice

Oblique view of a highly generalized animation of a subduction zone where an oceanic plate is subducting beneath a continental plate. (See sketch below for parts.) This scenario can happen repeatedly on a 100-500 year cycle. The process which produces a mega-thrust earthquake would generate a tsunami, not depicted here.

Animation Novice