The simulation at the source below  (number 4 on the list of required reading and sources; see the Background Materials for this module) allows you to experiment with many of the variables that produce sound when an object is hit or scratched.  The website contains a good explanation of the variables, which include hardness, base frequency, duration, and pluck time.

University of British Columbia (n.d.).  Sound simulation.  Retrieved on March 1, 2008, fromhttp://www.cs.ubc.ca/spider/kvdoel/sound_demo6.html

Because this simulation presents so many possibilities, the assignment is open-ended.  Choose one object (for example, the circular plate) and experiment with different values of the parameters governing sound generation.  Organize your work as follows.

Try striking or scraping the object at three different points.  For the circular plate, this could be the edge, the center, and halfway in between.

Systematically vary the parameters (hardness, base frequency, etc.), one at a time.  Summarize your conditions, and the results, in a table.

Be sure to click on the “Build” button every time you change the parameters, or the change won’t go into effect.  “Strike” or “scrape” the object by clicking on it.  (Be sure your speakers are connected and the volume is turned up, but not too far up.  You’ll scare the family pets to death.)

Write a two or three page paper summarizing your results, and post it to CourseNet.

SLP Assignment Expectations:

In general, SLPs are expected to possess the attributes of precision, clarity, breadth, depth, and applicability.  Not all of these are relevant to the answer to every problem in the SLP.  When it is relevant, the evidence for each attribute is as follows.

• Precision:  Numerical answers are calculated correctly, to the correct number of significant figures.  When a simulation is used, the results are accurate.
• Clarity:  The problem is restated in its simplest form.  Relevant variables are identified.  Formulas are algebraically rearranged, as necessary.  All the mathematical steps are shown, in logical order.
• Breadth:  Where discussion is required, the question is placed in context.  Alternatives are considered.
• Depth:  Where discussion is required, the question is examined in detail.  No relevant aspect of the question is omitted.
• Applicability:  When required, the practical importance of the principle or phenomenon is accurately described.

Note: URL verified on June 10, 2012. If an assignment requires that you include a source in a reference list, then you should verify that the source is still available, and enter the date you performed the verification.

A general treatment of wave motion and acoustics can be found at Wolfram Researh (2007) and Georgia State University (n.d).  Russell (n.d.)  provides a good discussion of the Doppler effect and sonic booms. The University of British Columbia (n.d.) site  is a simulation used in the SLP.

As before, you should feel free to surf the Web as needed for additional sources of information.

Required Materials

Georgia State University (n.d.). Sound and hearing. Retrieved on <Date: See note above>from http://hyperphysics.phy-astr.gsu.edu/hbase/sound/soucon.html

Russell, D. (n.d.) The Doppler effect and sonic booms. Retrieved <Date: See note above> fromhttp://www.kettering.edu/~drussell/Demos/doppler/doppler.html

University of British Columbia (n.d.). Sound simulation. Retrieved <Date: See note above> fromhttp://www.cs.ubc.ca/spider/kvdoel/sound_demo6.html

Wolfram Research (2007). Eric Weisstein’s world of physics – Acoustics. Retrieved <Date: See note above> fromhttp://scienceworld.wolfram.com/physics/topics/Acoustics.html

Additional Materials

CK-12  Foundation (2011).  CK-12 flexbooks (Index page).  Retrieved <Date:  See note above> from http://www.ck12.org/flexbook/

Khan, S. (2011).  Khanacademy (Index page).  Retrieved <Date:  See note above>  from http://www.khanacademy.org/