Excellent video from the EarthScope project, showing the seismic waves from the August 23rd earthquake zipping across the United States. Note that the height of the wave was only 20 micrometers (20 millionths of a meter or 0.02 mm) as it passed through the midwest.
One question that might occur is, why are there so many seismic stations in the middle of the continent? My guess is that it has to do with monitoring of the New Madrid fault zone, which produced
More details about the earthquake can be found on its IRIS page.
Last year, for an IRP, one of my students did the experiment measuring the speed of light (and the wavelength of the waves) using marshmellows in a microwave. The video above (via Gizmodo) shows the pattern of the microwaves using some neon lights embedded in plastic. The video below, from MythBusters, shows superheated water in action; something I demo every time I make tea-water in the microwave.
A change of perspective can give the most amazing insights. I find macro photographs, particularly of insects, to offer a stunningly refreshing view of these nuisances. Luc Viatour, whose image is posted above, has some wonderful, copyright permissive, pictures.
Photography, with it extensive use of refraction and reflection is a great avenue to talk about waves and their properties. Macro photography can be quite effective at striking the imagination and getting into taxonomy and entomology.
Stream of American History at the Corinth Civil War Interpretive center.
The Memphis to Charleston line was the only railroad that linked the East Coast of the Confederacy to the fertile Mississippi River Valley. At a time when the fastest way to move troops, supplies and commerce was by river or rail, the Memphis and Charleston railroad was essential (this was well noted in Robert Black’s “The Railroads of the Confederacy”). Cutting the railroad was an important objective of the Union. Cutting it at Corinth Mississippi would also cut the Mobile and Ohio Railroad line which linked the north and south of the Confederacy. Thus the Battle of Shiloh, where the Union could disembark its armies using the Tennessee River, and soon after, the Battle of Corinth.
The Civil War Interpretive Center in Corinth (this is also a good reference) does a nice job of presenting the details of the battles for the town, and their video presentation, with different images projected on multiple screens in a circular room was quite good (though there was a lot of information and you did not know quite which screen to focus on, so some students had trouble keeping track of it all).
Standing waves: turbulence in the stream of American history.
The most interesting part of the center is the Stream of American History which is a wonderful place to learn about metaphors. The stream starts with a fountain that overflows through 13 notches cut in the rim of the basin into a shallow water course that gradually widens as more states are added to the U.S. In the first reach of the stream there are impediments in the paved stream bed that create turbulence, harbingers of the war to come (they create nice standing waves which is an additional point in their benefit).
The 13th Amendment.
When the stream gets to its main focus, the civil war, large granitic blocks, cut into prisms and labeled with the names of the battles, break the stream into two before it finally merges again as it reaches the reflecting pool.
I threw my students at the Stream without telling them what it was. The only hint I gave was that it was a “large metaphor”. There were enough clues that they could figure it out. They wandered around it individually, with their pencils and notepaper for 15 minutes (I required that they write down their interpretation, then we got them together to pool their thoughts.
The stream is a very nice puzzle, and the National Park Service has a good key (pdf). It was a good way to end our immersion trip, and it gave the students something to think about on the long drive home.
[googleMap name=”Corinth Civil War Interpretive Center” width=”400″ height=”350″ mapzoom=”4″ mousewheel=”false” directions_to=”false”]501 West Linden Street, Corinth, MS[/googleMap]
[googleMap name=”Lake Catherine State Park” description=”Lake Catherine State Park” width=”490″ height=”490″ mapzoom=”12″ directions_to=”false”]1200 Catherine Park Rd, AR 71913-8716[/googleMap]
Just got back from an immersion trip to Arkansas. Every sixth week we get out of the classroom for the week and try to integrate what we’ve learned in the previous five. We’re out there, sometimes visiting somewhere history happened, sometimes hiking in the woods, and I wonder why we don’t spend all of our time outside the classroom. The kids get so much out of just exploring, and there is just so much that sparks the imagination.
Anyway, we hit Central High School, the Clinton Library and stayed and hiked at Lake Catherine State Park (see the map above). We also had a lesson on cameras that tied into our discussion of waves last cycle. I expect to post about each of these, they were all quite good.
There are a lot of Earth Science applications that deal with waves. Seismic waves from earthquakes are a major one that is particularly pertinent after the recent Haitian earthquake. There are quite a number of lesson plans dealing with seismic waves at Larry Braile’s website. Most of the lessons are as practical demonstrations pdf’s and some use downloadable software (Windows only unfortunately), but there are some online applications as well.
In terms of online resources, the IRIS network, produces nice maps of recent earthquake locations. It also has a good page with “Teachable Moments” regarding recent earthquakes. These include the above video of why the Haitian earthquake did not produce a tsunami.
Although it’s not directly related to waves, I particularly like the thermal convection experiment on Braile’s website. It provides, with a baking dish, a sterno can, some water and some thyme, a great example of the convection in the Earth’s mantle that drive plate tectonics.
