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Center for Faculty Excellence


Using Laptops in the Classroom:  Faculty Experiences
Laptop Physics 202

by Robert G. Fuller
Visiting Professor, Dept. of Physics, USMA
Professor of Physics, UNL
Spring, 2000

Shortly before the Christmas holiday of 1999, I was issued a Toshiba Satellite 4030 CDT laptop computer for use in a laptop section of 16 cadets in Physics 202 for the spring semester, 2000. Each of these cadets was issued the same kind of laptop computer with the same installed software. These 16 cadets were in the same section of Mathematics 206 course to be taught by Major Benson in the ACTL classroom in Thayer Hall (*Please Note: the ACTL is now located in 121 Jefferson Library*). The physics classroom, Bartlett Hall 209, was outfitted with a wireless communication system a few days after the start of the semester. The wireless system, in combination with the Timbuktu™ software on each laptop, enables the laptops to communicate directly with the computer in the cabinet in Room 209 and hence to be connected to the USMA internet system. Furthermore, the cabinet computer can access any of the computers connected to it via the wireless system. Hence, the instructor can see what is on the computer of any of the cadets and can also, with permission of the cadet, take over control of a laptop. Major Hamilton suggested that if the cabinet computer observed the instructor's laptop and then the instructor's laptop observed a cadet laptop that image could be projected for the class to see via the in-class projection system. However, this plan did not work, primarily, I think, because of the speed limitation of the communication software.

I began the semester with the commitment to have a laptop activity every day in class to demonstrate the useless of a laptop in learning physics. However, the commitment lasted less than a week. The difficulty of using the laptops effectively in class with the cadets and still dealing with the required physics content soon became impossible for me.

  • First lesson:  Bringing computers into the physics classroom for instructional purposes requires a substantial rethinking of the physics curriculum.
  • I had previously experienced this in the computer intensive physics course I taught at UNL. I'm not sure why I forgot it so soon. The cadets chosen for the laptop section were students who had been pretty successful in Physics 201. We did not want the extra task of using the laptop computers to threaten any of the cadets with failure to pass Physics 202. The cadets were informed that they would not need to bring their physics textbook to class, just the laptop with the CD-ROM that had been issued to them. That CD-ROM contained all of the textbook, plus additional learning materials. In particular, the CD-ROM included some interactive problem-solving activities that were designed to help the cadets learn how to solve physics problems. During the first class period, then, having been warned in advance to bring their laptops and CD-ROMs to class, I discovered that only 10 of the 16 cadets were actually able to run the CD-ROM on their laptops.
  • Second lesson:  Cadet skill level at using computers is much lower than one would expect.
  • In general, they only know the few tasks that they do over and over again, mostly word processing, e-mail and websurfing, I think. More demanding tasks such as interactive problem solving, writing formulas in a spreadsheet, using MathCad, etc., are difficult for many of the cadets.
  • Third lesson:  If computer skills are to be an important part of a course those skills must be explicitly taught in the course.
  • In general, this means taking some class time to deal with keystrokes and the reasoning needed to figure out what keystrokes to use. Before falling behind the Physics 202 syllabus I was able to develop and teach some spreadsheet skills in the classroom. In addition, I developed a style of giving graded homework in which each cadet had a different numerical result, based upon some personal number. I then used a spreadsheet with correct answers in it to grade the homework. See Appendix B, Activity 1.
    Over the course of the semester I did find some excellent physics websites that provided the cadets with a variety of additional learning experiences. However, these websites needed to be carefully examined and effective ways to incorporate them into the course needed to be developed. This required quite a bit of extra time. See Appendix B, Activities 2 and 3.
  • Fourth lesson:  Integrating physics websites in an effective way into a course takes more than just finding the website.
  • Additional preparation time is required to incorporate such sites into the syllabus.

Recommendation One:

Some use of websites for teaching needs to become a part of the New Instructors Training program. A systematic process of finding and integrating new websites into the core course syllabi needs to be developed.

Many of the laptop activities that I tried with the cadets did not seem to produce effecive learning. Also, after getting the wireless system up and running in the classroom I discovered that I was the only faculty member at USMA this semester who was trying to use the Timbuctu software actively in the classroom. I needed some one to talk to about ideas for using the computers and software in class.

Recommendation Two:

An interdisciplinary team of USMA faculty who are trying, or have tried, laptop teaching needs to meet together on a regular basis to share ideas and provide support for one another. Interactive, in-class laptop teaching is difficult work and, to my knowledge, no real effective models have yet to be developed in the USA using this type of instruction for students at this level.

I do not consider my use of the laptops this past semester as effective or innovative. I think I can see how to get to effective and innovative use of laptops in an interactive classroom setting from where I was, but I was not able to get there. I still believe laptops can offer us wonderful possibilities for more effective teaching and learning of physics, but we need much more experience before we figure out how to do it best.

Recommendation Three:

The USMA physics faculty needs to explore laptop teaching in a variety of settings. I think it might be easier to develop interactive laptop methods in a higher level course where the syllabus contraints are not as strict as in the core course. At UNL we had some success with using computer algebra software in the classical mechanics course for physics majors.

Laptop Physics USMA - 2000

  • Present system:
    • Wireless communication in the classroom
    • Timbuktu software-observe/control
  • Advantages:
    • Inexpensive, little change in classroom design
  • Disadvantages:
    • Access speed
  • Minimum requirements:
    • Cadet access to laptops
    • Instructor access to laptop
  • In-class possibilities:
    • Web-based activities
    • Applications software, Excel, Maple, Mathcad
    • Cadet/instructor developed materials
  • Experiences this semester:
    • Little effective use in the classroom
    • Cadet skill level not high
    • Found some excellent web materials
  • Recommendations:
    • Adequate instructor preparation
    • Add some related activities to NIT
    • Develop a cadre of "laptop" futurists in the department and at USMA
    • Keep a wireless room to continue department experimentation

Appendix B

Activity 1 - Using a Spreadsheet

Physics 202 Instructor's Points Activity (15 IPs)

Computing Potential Using Excel

You can use a spreadsheet as a map of the x-y plane, where the center of each cell is at a given location as shown in the handouts from class. For this case the origin of the x-y coordinate system is chosen to be at the center of spreadsheet cell B17. Each cell is assumed to be 0.1 m square.

  • Set the four particles at locations in the x-y plane by placing them at locations given by the last eight digits of your social security number and the look-up table below:
  • SSN Digit Number to use
    0 0.30
    1 0.40
    2 0.50
    3 0.60
    4 0.70
    5 0.80
    6 0.90
    7 1.00
    8 1.10
    9 1.20
  • The eight digits give you the x and y coordinates of the four particles in the order of x1, y1; x2, y2; etc. For example if the last eight digits of your SSN are 12-34-5678, your four charges would be:
    • Q1 at (0.40,0.50)
    • Q2 at (0.60,0.70)
    • Q3 at (0.80,0.90)
    • Q4 at (1.00, 1.10).
  • Assume that the four particles have the following charges, in FULLERS:
    • Q1 = -3.6 F {so it has a positive charge}
    • Q2 = -1.2F {so it has a positive charge}
    • Q3 = +1.2 F (so it has a negative charge}
    • Q4 = 3.6F {so it has a negative charge}
  • Locate your four charges in speadsheet according to your SSN digits.
  • Locate your four charges in speadsheet according to your SSN digits.
  • Once you have got your charges properly located in your spreadsheet, use the equation for potential to compute the potential at the center of each cell of the spreadsheet, for (0.0,0.0 to (1.5,1.5)
  • Show the equipotential lines, either by printing out the spreadsheet and drawing equipotential lines for every 5 volts, or use the graphing capability of Excel to draw a three dimensional plot with the potential plotted as a function of x and y.

Explanatory Notes

  • A point object with a charge of 1 FULLER of electrons will cause an electric potential of exactly -1V to exist at exactly 1 meter from the object. 1 FULLER = 6.944614 x 109 electrons.
  • COLUMN( ) is the function in Excel that returns the number of the column of the argument.
  • ROW( ) is the function in Excel that returns the number of the row of the argument.
  • $ makes the reference an absolute reference so it stays the same in all cells.
  • Square cells in a spreadsheet have a row height six times the column width, e.g. a column width of 5 and a row height of 30. Or for smaller cells and fonts, width 4, height 24.

Print out your spreadsheet and draw your equipotential lines on it or print out the spreadsheet and the accompanying graph from Excel.

Activity 1 - Using a Spreadsheet - In class tutorial

Plotting Electric Potential Using A Spreadsheet

You can use a spreadsheet as a map of the x-y plane, where the center of each cell is at a given location as show below. For this case the origin of the x-y coordinate system was chosen to be at the center of spreadsheet cell B17. The number shown in each cell is the electric potential, in volts, at the middle of that cell, where V=0 at infinity.

This is the formula for the potential at (0.0,1.5) {cell B2} when there is a charge of 5 FULLERS at (0.4,0.9) (cell F8}. =-10*$F$8/SQRT((COLUMN(B2)-COLUMN($F$8))^2+(ROW(B2)-ROW($F$8))^2)

Explanatory Notes

A point object with a charge of 1 FULLER of electrons will cause an electric potential of exactly -1V to exist at exactly 1 meter from the object. 1 FULLER = 6.944614 x 10^9 electrons.

COLUMN( ) is the function in Excel that returns the number of the column of the argument. ROW( ) is the function in Excel that returns the number of the row of the argument. $ makes the reference an absolute reference so it stays the same in all cells.

Activity 2 - Using a Web Site

Physics 202 Drawing Equipotential Lines

Website:  http://webphysics.davidson.edu.

From this page, click on Physlets. From the Physlets page, click on Chapter 9. On the Chapter 9 page, click on Electrostatics. On the Electrostatics page, click on Problem 2.

  • Set the four charges as locations on the screen by dragging them around with your mouse to locations given by the last eight digits of your social security number and the look-up table below:
  • SSN Digit Number to use
    0 0.30
    1 0.40
    2 0.50
    3 0.60
    4 0.70
    5 0.80
    6 0.90
    7 1.00
    8 1.10
    9 1.20
  • The eight digits give you the x and y coordinates of the four charges in the order of x1, y1; x2, y2; etc. For example if the last eight digits of your SSN are 12-34-5678 your four charges would be:
    • Q1 at (0.40,0.50)
    • Q2 at (0.60,0.70)
    • Q3 at (0.80,0.90)
    • Q4 at (1.00, 1.10).
  • Assume that the screen distances are given in meters.
  • Locate your four charges on the screen in problem 2 according to your SSN digits. If you click in the box on the screen it will refresh and redraw the electric field lines.
  • Once you have got your charges properly located in the grid in Problem 2, you want to convert that screen image to a printed image so you can draw the equipotential lines on it.
  • Once you have pasted the web graphic in Word stretch it to fill the upper part of a page, i.e. make it a large square about 16cm by 16cm.
  • On your enlarged printed image draw equipotential lines.
  • Blue lines for positive potentials and red lines for negative potentials.
  • Draw at least seven lines of each color on your graphic.
  • Determine and state the sign (+ or -) and approximate relative magnitude of each of the four charges.
  • Explain in words how and where you decided to locate the various equipotential lines.

Note:  One way to get a web graphic into Word - press "Print Screen" {Alt + PrtSc} to copy the whole screen image to your computer clipboard. Then paste the whole screen into to Paint. Use the Select tool in Paint to choose the part of the screen you want to use. Then copy and paste that into Word as a Paste Special picture that does not float above the text.

Activity 3 - Using the Web for Homework

Physics 202 Lenses and Mirrors (100 instructor points)

For full credit: Due on or before 1700, Monday, May 8, 2000

Calculate your personal focal length in centimeters (PFL) by putting a decimal to the right of the second non-zero digit in the last four digits of your social security number and then round it off to the tenths place.

Your PFL will be a number between 10.0 and 99.9.

Examples: 4139 is 41.4 cm; 0837 is 83.7 cm.

Be sure to include your name and section on your work and follow the USMA rules for proper documentation of graded homework (especially the sources of your diagrams, see below).

(20 points) Compute your PFL and show it to the correct number of significant figures and give its units.

Each of the following parts of the assignment is worth 10 points each. To get full credit for a part you must:

  1. (6 pts) include a three-ray diagram showing the object, lens, or mirror, and image. You may make a scale drawing of the system, or you may copy and paste a drawing from an appropriate website such as http://surendranath.tripod.com/curvsurf/CurvSurf.html or http://www.phy.ntnu.edu.tw/java/Lens/lens_e.html
  2. YOU MUST CLEARLY DISTINGUISH ON YOUR DIAGRAM THE DIFFERENCE BETWEEN REAL AND VIRTUAL RAYS AND IMAGES IN ORDER TO OBTAIN FULL CREDIT.
  3. (2 pts) select the proper kind of thin lens, or mirror, and choose a proper object location and include a calculation using the thin lens, or mirror, equation for your PFL and the object location you choose to verify that the image satisfies the criteria required. This calculation must include the object location, the image location and the magnification, with proper units.
  4. (2 pts) a brief verbal description, one paragraph, that describes the quantitative values and the properties of the system including the properties of the object, the lens, or mirror, and the image.
  5. Eight parts (10 points each) set up each part so that the system results in an image with the listed properties:
    1. Thin Lens Images:
      1. inverted, real, reduced
      2. inverted, real, enlarged
      3. upright, virtual, enlarged
      4. upright, virtual, reduced
    2. Mirror Images:
      1. inverted, real, reduced
      2. inverted, real, enlarged
      3. upright, virtual, enlarged
      4. upright, virtual, reduced
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