Seismic Slinky: Modeling P and S waves

p.p1 {margin: 0.0px 0.0px 6.0px 0.0px; line-height: 14.0px; font: 11.0px 'Myriad Pro'} span.s1 {font-kerning: none} span.s2 {text-decoration: underline ; font-kerning: none; color: #005ede}

Students will produce P and S waves using a Slinky© to understand how seismic waves transfer energy as they travel through solids. All types of waves transmit energy, including beach waves, sound, light, and more. When an earthquake occurs it generates four different types of seismic waves).  We will focus on two of these:  Compressional-P (longitudinal) and shearing-S (transverse) “body waves.”  These travel through the Earth with distinct particle motion and predictable speed. 
P waves travel at over 360 km/hr (225 mi/hr) through solid rock, compressing and dilating the Earth in the direction they are propagating, much like sound waves do. They also travel 60% faster than the shearing S waves. It is this velocity difference that helps seismologists locate an earthquake’s epicenter.


By the end of the exercise, students should be able to:

  • produce both P and S waves using a Slinky© 
  • use the model as a tool to observe and understand wave properties
  • describe the difference between P  and S seimic waves based on the direction of particle motion relative to the direction of propagation

Level: Novice

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