Making Waves: Seismic Waves Activities and Demonstrations Larry Braile, Purdue University email@example.com, web.ics.purdue.edu/~braile Sheryl Braile, Happy Hollow School West Lafayette, IN CSTA Conference, October 2009 Palm Springs, CA This PowerPoint file: http://web.ics.purdue.edu/~braile/new/SeismicWaves.ppt
Seismic Waves • Slinky – P, S, Rayleigh, Love waves; Reflection and transmission; energy carried by waves; elastic rebound/plate motions and the slinky; 5-slinky model – waves in all directions, travel times to different distances. • Human wave demo – P and S waves in solids and liquids. • Seismic wave animations – P, S, Rayleigh, Love waves; wave motion; wave propagation activity. • Seismograms – Viewing seismograms on your computer (AmaSeis software). • Seismic Waves software – Wave propagation through the Earth.
Why use several approaches for teaching about seismic waves? • Fundamental concept (worth spending time on) • Different approaches for different settings or size of group • Different learning styles • Reinforce with more than one approach • Demonstrations, animations and hands-on activities • Use one or more approach for authentic assessment
Elasticity – a property of materials that results In wave propagation and earthquakes * Difference in length of spring before and after adding mass.
Slinky and human wave demo and wave tank and elasticity experiments: http://web.ics.purdue.edu/~braile/edumod/slinky/slinky.htm http://web.ics.purdue.edu/~braile/edumod/slinky/slinky.doc http://web.ics.purdue.edu/~braile/edumod/slinky/slinky.pdf
A simple wave tank experiment – a ping pong ball is dropped onto the surface of the water; small floats aid viewing of the waves; distance marks on the bottom of the container allow calculation of wave velocity.
Seismic waves and the slinky(also, see the 4-page slinky write-up at: http://web.ics.purdue.edu/~braile/edumod/slinky/slinky4.doc) • P and S waves • Love and Rayleigh waves • Wave reflection and transmission • Elastic rebound • Waves carry energy • The five slinky model (waves in all directions and different travel times to different locations – the way that earthquakes are located)
Seismic waves carry energy. Observe the shaking of the model building when P and S waves are propagated along the slinky.
The 5-slinky model for demonstrating that seismic waves propagate in all directions and the variation of travel time with distance.
The human wave demonstration illustrating P and S wave propagation in solids and liquids.
Wave animations Animation courtesy of Dr. Dan Russell, Kettering University http://www.kettering.edu/~drussell/demos.html Seismic Wave animations(Developed by L. Braile)http://web.ics.purdue.edu/~braile/edumod/waves/WaveDemo.htm
Dan Russell animations – The people wave Animation courtesy of Dr. Dan Russell, Kettering University http://www.kettering.edu/~drussell/demos.html
Dan Russell animations – Rayleigh wave Direction of propagation Animation courtesy of Dr. Dan Russell, Kettering University http://www.kettering.edu/~drussell/demos.html
Compressional Wave (P-Wave) Animation Deformation propagates. Particle motion consists of alternating compression and dilation. Particle motion is parallel to the direction of propagation (longitudinal). Material returns to its original shape after wave passes.
Shear Wave (S-Wave) Animation Deformation propagates. Particle motion consists of alternating transverse motion. Particle motion is perpendicular to the direction of propagation (transverse). Transverse particle motion shown here is vertical but can be in any direction. However, Earth’s layers tend to cause mostly vertical (SV; in the vertical plane) or horizontal (SH) shear motions. Material returns to its original shape after wave passes.
Rayleigh Wave (R-Wave) Animation Deformation propagates. Particle motion consists of elliptical motions (generally retrograde elliptical) in the vertical plane and parallel to the direction of propagation. Amplitude decreases with depth. Material returns to its original shape after wave passes.
Love Wave (L-Wave) Animation Deformation propagates. Particle motion consists of alternating transverse motions. Particle motion is horizontal and perpendicular to the direction of propagation (transverse). To aid in seeing that the particle motion is purely horizontal, focus on the Y axis (red line) as the wave propagates through it. Amplitude decreases with depth. Material returns to its original shape after wave passes.
You can download the animations separately to run more efficiently: (http://web.ics.purdue.edu/~braile/edumod/waves/WaveDemo.htm). A complete PowerPoint presentation on the Seismic wave animations is also available at: http://web.ics.purdue.edu/~braile/edumod/waves/WaveDemo.ppt Demonstrate the AmaSeis software for displaying and analyzing seismograms; software available at: http://bingweb.binghamton.edu/~ajones/ A tutorial on AmaSeis and links to seismograms that can be downloaded and viewed in AmaSeis available at: http://web.ics.purdue.edu/~braile/edumod/as1lessons/UsingAmaSeis/UsingAmaSeis.htm The IRIS Seismographs in Schools program: http://www.iris.edu/hq/sis
IRIS AmaSeis Software (developed by Alan Jones, SUNY Binghamton, NY) 24-Hour Screen Display Extracted Seismogram The AS-1 Seismometer
Teaching Modules and Tutorials: http://web.ics.purdue.edu/~braile/edumod/as1lessons/as1lessons.htm
The Seismic Waves program From Alan Jones, SUNY, Binghamton http://bingweb.binghamton.edu/~ajones/ Earthquake * Cross Section Through Earth Wavefront Ray Path Stations for Seismograms Seismograph Ray Path is perpendicular to wavefront