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Superposition Physlet

by Wolfgang Christian
 

Ratings

Overall Rating:

4 stars
Content Quality: 4 stars
Effectiveness: 4 stars
Ease of Use: 4 stars
Reviewed: Apr 21, 2001 by Physics
Overview: The physlet has a range of sections and activities varying from easy to challenging. The student determines the wavelength and frequency for specific traveling waves. The student must determine parameters or functional form for waves with specific properties (like a node at a specified location or standing wave). The item contains several activities relating to superposition, standing waves, traveling waves, beats and dispersion. A wide range of functions can be used.
Learning Goals: To understand how waves combine to produce a varied of definite special case results (e.g. standing waves, beats, traveling waves).
Target Student Population: Lower level undergrad
Prerequisite Knowledge or Skills: Trigonometry, traveling waves, standing waves and interference.
Type of Material: Homework or Lecture/Demo
Technical Requirements: None

Evaluation and Observation

Content Quality

Rating: 4 stars
Strengths: When a student calculates the wave characteristics required for a specific result, the Physlet performed very well and produced the appropriate visual results. The item contains three different exampes. The physlet is can be customized through scripting. Example one may be of particular use in introductory physics courses since this contains a specific example and requires specific measurements to be made. Students can be instructed to measure wavelengths, velocities of waves, frequency, group velocity. Also includes standing wave effects and more.
Concerns: The basic module contains three different examples, if used as presented. This may confuse students. One of these contains additional lessons. The layout and nature of each of the examples differs and may be useful to very different types of students. The function entry boxes contain two strange features. When the value of the function goes through multiples of about 3100, a vertical line is plotted. Also the enter button must be used for all function entries. If you hit Enter (keyboard key) from the function entry box then the original page reloads but the entered function is not displayed unless the "Enter" button is used.


General Comments on Quality: Overall this is a quality item. It is flexible and contains several examples and exercises. One component of particular interest to introductory physics students is the standing wave example.


Potential Effectiveness as a Teaching Tool

Rating: 4 stars
Strengths: Recommended Use(s) for Material: Lecture/Demo, Homwork, Recitation


Calculated results are in very good agreement with the visual display. Students can experiment on their own. This reinforces many of the mathematical points made in introductory courses covering wave topics. Nice demonstration of superposition. This can be extended to provide the student an introduction into Fourier synthesis. The material can be used in lectures or have students complete measurements and answer questions as homework. There is sufficient breadth of material that homework could be assigned from different modules for a variety of different courses. The first two examples contain several problems or suggested student exercises.

Concerns: Use(s) Material is not Suited For: Tutorial


Time distance scales have no units. This must be provided with instructions for use of the applet. It may be difficult for introductory students to connect the general picture of say a standing wave on a string to the displayed picture. More detailed exercises or worksheets may need to be incorporated for students to get the most out of these physlets.


General Comments on Effectiveness: This is an effective teaching tool for the Introductory Physics course and possibly others. Several physical concepts can be demonstrated. Wavelength, frequency, and velocity of individual waves can be measured. Other functions of position and time can be displayed. Travelling functions (functions of x-vt) can be examined. All of this in addition to superposition properties.


Ease of Use for Both Students and Faculty

Rating: 4 stars
Strengths: Use of this applet is easy to learn and understand. The steps required to enter a wave and to make measurements are very straightforward. Documentation is available to support additional use and development of this physlet.
Concerns: Since there are links to different examples, the controls are not uniform throughout. One example uses "Enter" another "Change". The method of entering or editing parameters can seem awkward because of this non-uniformity. There is not a link to or directions to explain what the function entry syntax is or the allowed list of math functions within physlets.


General Comments on Usability: Effective and usable teaching tool. Instructors may need to modify the physlet scripts to ensure a uniform environment and more information on using the applet. The items are meant as examples of the use of the superposition physlet. A good source for learning to script Physlets is the text Physlets: Teaching Physics with Interactive Curricular Material by W. Christian and M. Belloni.

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