SIX IDEAS THAT

SHAPED PHYSICS

FOURTH EDITION

Computer Apps for Six Ideas

IN THIS SECTION

PHILOSOPHY

 

Advances in computer software make certain things accessible to introductory students that have been inaccessible in the past. The Six Ideas project includes a variety of supporting web-based apps that enable new kinds of instruction. Broadly, the provided apps fall into three categories:

  • Apps that simulate a physical situation or illustrate a physical model (e.g. Drude)
  • Apps that provide quick access to data (e.g. NucInfo)
  • Apps that automate certain kinds of calculations (e.g. Newton, StatMech, SchroSolver)

Some of these apps (particularly those in the last category) have been integrated into the text presentation because they augment students' abilities in such important ways. Others are optional.

The Six Ideas project, however, does not require students to learn computer programming in any language. Requiring students to write software can provide huge benefits in principle, but also huge costs. We considered this early on but eventually rejected it, because it requires too much overhead and because even simple computer languages are not friendly enough for students to focus on the physics instead of the computer language.

Instead, our guiding principles, particularly with apps in the final category, have been

  • Keep the app's task as focused and simple as possible.
  • Design user interfaces that as obvious and foolproof as possible.
  • Ensure that what the app is doing is as transparent as possible.

In particular, for apps that automate certain kinds of calculations, we require (when possible at all) that each student practices the algorithm by hand before seeing the app, and then verifies that the app simply automates what he or she could do by hand given sufficient time. We consider this an very important principle that ensures that the student does not see the app as a black box, but rather as an extension of his or her abilities.

Applications such as WolframAlpha also make certain kinds of symbolic calculations accessible that were not before. The 3rd edition of unit T takes advantage of this capability to explore certain ideas that require evaluating some fairly nasty integrals.

THE APPS

 

  • ProbViewer (all units). Students use this app to display homework solutions. The professor defines a password-protected list of solutions and a time-window for each solution.
  • Newton (unit N). This app automates the process of constructing a trajectory diagram (see chapter N3). Students can define the object's initial position and velocity, the time-step, and how to calculate the acceleration at every point. The unit N text and homework problems refer to this app often, as we can use it to predict an object's motion even when a mathematical analysis is difficult or impossible.
  • EField (unit E). Use this app to draw a three-dimensional picture of the electric field of charge distributions you can define. This app automates the process of calculating electric field vectors by using the formula for the field of a point charge and the superposition principle. (as discussed in the book). This app is recommended as a possible class activity but is not mentioned in the book (though it was used to generate some figures).
  • BField (unit E). Use this app to draw a three-dimensional picture of the magnetic field of current distributions you can define. This app automates the process of calculating electric field vectors by using the formula for the field of a point charge and the superposition principle. (as discussed in the book). This app is recommended as a possible class activity but is not mentioned in the book (though it was used to generate some figures).
  • Equipotentials (unit E). Use this app to draw equipotential diagrams of two-dimensional charge distributions that you can define. This app is recommended as a possible class activity but is not mentioned in the book (though it was used to generate some figures).
  • Drude (unit E). Use this app to simulate and illustrate the flow of electrons through a metal as imagined in the Drude model. This app is recommended as a possible class activity but is not mentioned in the book.
  • Interference (unit Q). Use this app to simulate a one-quanton-at-a-time two-slit interference experiment. Students can vary the slit width, slit separation, quanton wavelength, and whether proximity detectors are active at each slit. The app is mentioned in problem Q5T.8, which provides an excellent class activity.
  • Spins (unit Q). Use this app to simulate user-defined experiments involving sequences of Stern-Gerlach devices (see chapters Q6 and Q7) and particle counters. This app is useful for checking results of calculations and illustrating the idea that experimental probabilities are uncertain. This app makes a great class activity, but is not mentioned in the text.
  • SchroSolver (unit Q). Use this app to calculate energy eigenfunctions for a quanton subject to various kinds of (user-adjustable) potential energy functions. This app is a core part of chapter Q12, and is described in that chapter in used in various problems. Students do learn both the numerical algorithm that this app uses and can also check that it is consistent with the eigenfunction sketching rules they learn in the chapter.
  • NucInfo (unit Q). This app provides a convenient user interface for looking up information about nuclei in a database. It provides a useful resource for class activities and for checking predictions about nuclear stability. It is not mentioned in the text.
  • StatMech (unit T). This app automates the construction of macropartition tables of the type appearing first in chapter T2. It is a crucial part of the unit T text and many homework problems refer to it. It is also great for class activities.
  • Equilib (unit T). This app simulates how an initially hot Einstein solid transfers energy to an initially cold Einstein solid through random transfers of energy between oscillators. It also illustrates the fluctuations that occur once the combined system reaches equilibrium. It is fascinating to watch and a great demonstration of the macroscopic process of equilibrium emerges out of random microscopic processes, but it is not mentioned in the text.
  • MBoltz (unit T). This very simple app allows students to numerically evaluate integrals of the Maxwell-Boltzmann distribution of molecular velocities between defined limits. It is an important part of chapter T6 and many homework problems use it.
  • Planck (unit T). This very simple app allows students to numerically evaluate integrals of the Maxwell-Boltzmann distribution of molecular velocities between defined limits. It is an important part of chapter T6 and many homework problems use it.

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