This review is of the Dynamics applets on this site
There are a large number of applets at this location, dealing with many different aspects of general physics. This review is limited to the subset under the "Dynamics" heading. This is not a complete coverage of dynamics, but contains some very interesting and unusal lecture/demo items.
Type of Material:
Lecture/Demo
Identify Major Learning Goals:
To help students better understand a variety of motions in classical mechanics through guided demonstrations.
Varies with applet, but generally introductory mechanics.
Content Quality
Rating:
Strengths:
Each applet in this group is well focused on some aspect of Newtonian dynamics, many dealing with situations that are hard to teach using static pictures. Most have introductory remarks that communicate the intent and suggest student activities. There is an applet that illustrates in a particularly effective way the motion of the center of mass of a dumbbell launched as a projectile. A two dimensional collision applet combines both the motion and vector analysis. These are clearly well thought out and well executed applet demonstrations. All applets provide control sliders to control selected simulation parameters.
Concerns:
Parameter ranges are sometimes too restricted -- most of the applets cannot show limiting cases. There are no instructor resources to allow others to quickly achieve the targeted learning goals. Most items do not need it, but some would be more useful to instructors if this were available.
General Comments on Quality: Overall, these applets are of excellent quality, from both a physics and programming point of view. Some of the simulations are a bit esoteric, but most deal with topics commonly covered in an intermediate classical mechanics course, though most are accessable to better students in the introductory course. Physical parameters are easily modified. The applets show qualitative aspects of motion, but most also have quantitative data that could be used by students to check an analytic assignment. Comments specific to particular applets are given below:
Block on Inclined Plane - Although somewhat esoteric and of limited use, it does clearly show vector acceleration relationships and gives a good impression of the motion from different frames of reference.
Collisions - A very nice applet that shows two-dimensional hard-sphere collisions in the lab frame,
CM frame, or both. The user can vary the impact parameter, the mass ratio, and elastic parameter. Any change to these parameters immediately updates the momentum vector diagram, even without running through the simulation. There is linked page of equations, which is totally confusing because of the large number of equations shown (nearly all of which are linearly dependent).
Center-of-Mass - Shows the trajectory of each mass and the center of mass of a dumbell in projectile motion. The initial CM speed, velocity, rotational speed, and angle are controllable. Changes in parameters instantly update the paths. This applet gives a good sense of individual particle and center of mass motion.
Potential Effectiveness as a Teaching Tool
Rating:
Strengths:
Recommended Use: Lecture/Demo
There are a variety of concepts illustrated by these applets that could enhance lectures and recitations. Many effectively deal with topics that are difficult to understand from static pictures.
Concerns:
Restricted parameter ranges in most applets do not allow them to be used effectively in discussing limiting cases. It would be nice if there were more readouts of physical parameters that would allow students to follow up with calculations.
General Comments on Effectiveness: Although the dynamics coverage of these applets is spotty, they can be very useful for in-class lecture/demos or guided analysis of motion for the specific cases treated.
Ease of Use for Both Students and Faculty
Rating:
Strengths:
Most applets have a launch button that only appears after the applet has fully loaded. This is a great idea that more developers should pay attention to. Most are also well-written from the point of view of the user interface (both input and output). The controls work as expected, with convenient automatic resets. In addition to the standard "Start" which shows the motion in a smooth,
continuous way, many have sliders that allow either step-by-step or rapid generation of trajectories. Parameters are easily set with sliders.
Concerns:
The java-based applet menu adds little value, and prevents linking directly to individual applets. There is a link to bypass this menu, but it does not organize the applets in the same way. The size of the applets cannot be changed, which might be a problem for in-class demo use.
General Comments on Usability: Applets are intuitive, and controls are logical. As they are, these applets can be usefully employed for lecture/demos. Some can also be used with little additional effort by instructors for guided problem solving in-class. (E.g., the "Roll, Hit, and Slip" has excellent potential for such use.) With moderate creativity and additional work on the part of the instructor, many of these items could also be effectively employed as homework assignments.
Creative Commons:
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