An Earthquake Adventure Afternoon at the Port Townsend, WA,
Marine Science Center

Earthquakes are both terrifying and fascinating. For residents of Western Washington, the threat of an earthquake is real, and scientists warn of a massive earthquake that will someday occur without warning. Yet earthquakes also reveal fascinating clues about a part of our planet we never see, deep below the earth’s surface.

Retired seismologist Dr. John Lahr has spent his life studying earthquakes and he enjoys sharing his passion for his field with students and teachers. The Port Townsend Marine Science Center is excited to offer visitors to its exhibits a special afternoon with John Lahr from 1 to 3 pm on Sunday, July 23. This visit is sponsored by the Incorporated Research Institutes for Seismology (IRIS).

“John’s program will replace our normal public program in the Natural History Exhibit,” said Judy D’Amore, Educator/Curator of the PTMSC Natural History Exhibit. “Our Earthquake Adventure Afternoon will offer children and adults the chance to take part in fun, thought-provoking activities John uses to explore questions like: What makes earthquakes happen?, How can we detect them? and How can we to design buildings that don’t fall down?”

Tectonics and Convection

Tectonic Globe

Make your own globe that shows the major tectonic plates from an old tennis ball. See: http://jclahr.com/alaska/aeic/taurho/globe.pdf

Tectonic Model of Spreading and Subduction

This model, with can be made from a shoe box, illustrates many of the key mechanisms of plate tectonics. See: http://jclahr.com/science/earth_science/
platemod/index.html

Graham Cracker Tectonics.

Illustrate plate tectonics with crackers (plates) sliding on chocolate frosting (asthenosphere). See: http://jclahr.com/science/earth_science/cr06/
workshop/activities/snack/snack_tectonics.html

Making the Asthenosphere (Silly Putty)

This material is elastic, but it also flows. These are also two characteristics of the asthenosphere on which the plates slide. See: http://jclahr.com/science/earth_science/cr06/
workshop/activities/sillyputty.html

Folding and Faulting

Squeeze box. By compressing layers of sediments, one can see how folding and faulting occur. See: http://www.exo.net/
~emuller/activities/The_Squeeze_Box.pdf

Elastic Rebound.

A block of wood, when pulled by a string of rubber bands, exhibits stick-slip motion similar to that seen on faults. See: http://jclahr.com/science/earth_science/tabletop/
earthshaking/index.html or http://www.iris.edu/edu/EQliteActivity1.htm

Bendable Core. A granite rock core is cut with a diamond saw and mounted to a board to create a demonstration of the elasticity of rocks.

Vibrations and Waves

Talking Strip. The plastic strip has bumps arranged so that sliding a fingernail along the strips generates the words "Science is fun." See:
http://jclahr.com/science/earth_science/talking_strips/talking%20strips.html

Three Slinky Model. The three slinky model can be used to show that the travel times to different locations (such as to seismograph stations) will be different. See: http://web.ics.purdue.edu/
~braile/edumod/slinky/slinky4.htm

Standing Wave Machine

Make and manipulate standing waves in a string. See: http://jclahr.com/science/earth_science/
standing_wave/index.html

Seismology – Recording the Vibrations

Seismograph.

A totally mechanical seismograph to illustrate the principal of recording ground vibrations. Details.

Table Top Seismology

Demonstrate the operation of a seismic sensor with a home-built model and a small refraction geophone. See: http://jclahr.com/science/earth_science/tabletop/index.html

Resonance and Buildings

Building model. To demonstrate resonance .
As an alternative to this model, this 3 MB video in wmv format: http://jclahr.com/science/earth_science/demos/building_model.wmv or this 8 MB video in mpeg format: http://jclahr.com/science/earth_science/demos/building_model.mpeg They show how spaghetti noodles and small marshmallows can be used to demonstrate resonance.

Spaghetti Building Models

See how strong a building you can design using small marshmallows and spaghetti. See: http://jclahr.com/science/earth_science/explor06/target16.html

Magnetism

Floating Magnets.

A few small magnets illustrate that like poles repel and opposite poles attract.

Reversible Magnetic Field.

The small globe contains a coil. The orientation of the magnetic field may be changed by reversing the battery wires.

Magnetic Globe. A rubber globe with a strong magnet inside uses staples to demonstrate the declination and inclination of a dipole field. For more information, see http://jclahr.com/science/earth_science/dipole/index.html. The Exploratorium also has a good write up on this demo. See http://www.exploratorium.edu/theworld/iceland/magnetism.html

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