This was EXCELLENT. Thank you very much for this insight into what a science fair judge is looking for. Although my children are already grown, I will give this to the parents of my 7-year-old grandson, so that it can be used as a guide! Once again, thank you, "JD" Cooley At 03:36 PM 4/17/01 , Sean-Thomas Morrissey wrote: >Hi seismometer Mom, > >I agree with Erich's comments. > >I have often been a judge for the local science fair, and have seen >many versions of paper mache' volcanos (models aka "Close Encounters" >providing no science), earthquake "predictions" based on caterpillars >(a result of selective hearsay and coincidence), and wooden seismometers >crushed by an ever increasing mass of bricks in an attempt to get >"results". > >My usual approach to a fair exhibit is to first try to find an explicit >statement of the scientific question of the display. This is the >"how do we know ...." or "Why does" or some hypothesis that can >be demonstrated by a simple experiment (beans grow faster in an >electric field). If there is no question or hypothesis, there can be >no scientific test or demonstration of a principle, and therefore, >no "results". For a seismograph or seismometer display, the question >is "how do we detect the faint ground movement of distant earthquakes". > >Then I look for some experiment to evaluate the question. Usually >the answer is known by science, so showing how we know it is >demonstrated by some replication of the physical experiment or, >in the case of like math or astronomy, a large poster detailing the >logical steps that lead to the conclusion is presented (some have >that ring of verbatim Brittanica, especially when a gross error in >copying is evident). > >So for the "how do we know" science display, a demonstration of the >core physics is usually presented within the amateur limitations of >the student. For a seismometer/seismograph, recording the relative >motion of a suspended inertial mass with respect to the moving ground >is the key concept. Amplifying the miniscule motion (0.001mm) >from a distant quake is more advanced. A comprehensive background >poster of earth/core wave propagation is easy to assemble. And a >poster with good graphics can detail all the concepts, including >wave propagation and quake location without having to build a >seismograph. A demo on a map on the table of triangulation of the >epicenter location from station S-P travel times represented by >using marked tapes is a nice interactive display. > >A fatal misconception is that some hardware something must be built >that should prove or demonstrate the point, (often overlooking the >practical alternative of borrowing a professional instrument and >then carefully labeling the key components.) This construction then >becomes the prime effort of the display even though the student >(parent) has not grasped the physics or science involved. Then the >display becomes an exhibit of the construction skills of the student >(parent), which often blindly copy some article. > >I have seen beautiful all-wood Lehman type sensors but made with >brass cabinet hinges and a brick for a mass with a pencil attached >that writes on a tablet placed under the front side. The student >got high marks because of the instructions: "slowly slide tablet >out while shaking the table"; the principle of the inertial mass >was proven, as was the registration of a the waveform passing with >time: ie "results". The display even noted that the table shaking >was about intensity MM-X, and referred it to a graphic about intensity. > >However, often the entire point is missed and the "results" are >faked; ie."simulated". One seismometer display had a lead pipe hanging >on a spring, with the attached pencil writing on a paper cylinder resting >on an open clock face (sort of turned by the minute hand). There was a >nice tracing of a teleseism, carefully labeled to agree with an >attached news clipping. But no current demonstration of how the >data was or could be made. (Fair judges often converge on a display >that challenges their ability to "make it work", and sometimes make >adjustments or add something that does make it work). > >The value of an exhibit is proportional to the time devoted to it. >A good high school project will take about a year, with the last >half devoted to building whatever and trying to make it work. >Then, in the case of a sensitive seismograph (with a magnification of >at least 1000,) you might have to wait a month for a significantly >large earthquake to record on it. > >But I have never seen any seismograph displays involving even rudimentary >electronics (moving coil/magnet and amplifier), but this is the >midwest rather than California, and although electricity is a >high school subject, the practical usefulness of it remains elusive. > >And a final note: "quick" and "easy" have nothing to do with science. > >Regards, >Sean-Thomas Morrissey >St. Louis University. > >PS: there is a design for a hardware store seismometer using modern >electronics that is neither quick (could be done in a devoted month) >nor easy (those darn electronics parts) described at: > >http://www.eas.slu.edu/People/STMorrissey/index.html > >stmseis.html" The STM-8 Leaf Spring Seismometer: Photos and Report >stmfigs.html" The STM-8 Seis: Figures, Schematics, Drawings >stmquakes.html" The STM-8 Seis: Recent Quakes, Data > > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>