Excerpts from User's and Reviewer's Comments on Chaos Demonstrations

"This is a very helpful program for my course in chaos, just concluded given by Professor Edward Spiegel in the Astronomy Department...The course uses other software but this seems much more user-friendly. It seems especially helpful in making it easy to 'push' the parameters into chaos." -- H. Middendorf, Columbia Gen. Studies Student.

"So far I am very pleased with this package of demonstrations. I appreciate the inclusion of biology since that is what I teach." -- Larry O. Miller, Biology Dept., Moorpark College

"Very interesting. A nice piece of work" -- Mark Tompkins, University of Southern California

"I had a lot of fun and look forward to more enjoyment and learning" -- Willard S. Grant

"Very well done. I'm impressed with the care and thoroughness of presentation, options, organization...Repeat - very well done." -- Paul Sandorff, Massachusetts Institute of Technology (retired)

"I give the program rather high marks for being good in several/many respects." -- Doug Davis, Chairman and Professor of Physics, Eastern Illinois University

"This is a very handsome and well put together program. The range of demonstrations and their implementations are very striking...I think this program could have a wide audience, both in terms of academic interest and technical background" -- Chuck Bilow, Wisc-Ware

"CHAOS DEMONSTRATIONS" is a once beautiful, amusing, and thought- provoking. With a few simple modifications [since made], it can be made quite user friendly. Science and math students at all levels should be able to learn something from the simulations and explanations. Students with imagination but no 'mind for math' will at least be able to see the amazing complexity that can come from mathematical equations. This reviewer looks forward to the eventual publication of this software package." -- Kenneth Gattis, North Carolina State University

"This is a lavish simulation program which generates graphics illustrating a number of situations which have been rediscovered in recent years, and are lumped together under the name of deterministic chaos...The software could be used by beginning students who have never heard of chaos. (There is even a simple multiple-choice quiz built in). Upper level students, who are probably familiar with Mandelbrot sets and driven pendulums, will find other advanced cases which will hold their interest. Faculty members with access to color monitors or projection panels could use this program as a demonstration tool. It would also be a valuable addition to a software library, since the excellent documentation makes it easily usable and understandable...This program fills a need which many faculty members have felt. Interest in chaos has grown to the point at which it has moved beyond specialists into the general community. This is a subject which is best appreciated by watching a live demonstration or developing simulation. It is nice to see a picture of a Julia set, but it is a step further to watch the points appearing, and to know how they are being selected. Almost everyone has seen a few simulations, but they are all collected here, and with clear documentation and explanation screens...The mathematics and the explanations are clear, and the simulations are timely and useful. The package deserves wide distribution." -- Edward Finkel, Fernbank Science Center

"This is an excellent package. I highly recommend it for promotion and distribution by Physics Academic Software...The program is well conceived and well executed...The intended audience is very broad and includes anyone with curiosity or interest in deterministic chaos and related developments in dynamical systems...The preselection of data has the merit that the user does not waste time trying many repetitive or uninteresting cases. Among the good points of this program are its selection of examples. The standard literature in this area assumes (or provides) familiarity with these examples, and any student who aims for a knowledge of this field should see this set of illustrations (readily accessible with minimum effort here) or their equivalent (rarely available). The user's manual is excellent. Its claim that one can use the program after only reading the preface is correct. The useful references are about all that is not available within the program as help screens. The instructor's manual is also excellent. It provides a more extensive and technical description of the examples, so that an instructor who is not an expert in the field can quickly learn enough to have confidence in presenting these illustrations in courses where they may not be the principal topic. The 'museum mode' self-running, interruptible demonstration is an excellent idea, well executed. We displayed the program in our physics lobby for several days (on a machine with only the cursor pad and a few other keys accessible) and it received a lot of attention. The chairman said that he saw a couple of ten year olds working at it for half an hour once. A few students explored it enough to come to me with bug reports [since fixed], but also commenting 'awesome!', and 'very nice'". There were some very good ways of presenting the computations employed here: On slow computations the data are first sketched crudely (spaced sample points, low accuracy), then filled in and improved. Multiple independent particles can be followed in some cases (e.g. the magnetic quadrupole) to show beautifully the sensitivity to initial conditions. Alternate coloring on successive iterations (e.g., Henon map) to allow following clearly the progress of many parallel examples. Also admirable is the flexible programming that left several parts of the program in modifiable text files: the explanation screens, the quiz, and the museum demonstration sequence. You should provide this program to prospective authors. They might improve their own work by stealing hints from the good design of this program." -- Anonymous reviewer for Physics Academic Software

"You have a winner here. It is well done, informative and of use to all levels of physics students. The write ups are very good. There is ample graphics for the introductory physics students and equations with changeable parameters for advanced students." -- Dr. Philip Gash, Cal State University

"...the program seems well-targeted, offers a reasonable amount of interactivity, and has a clean, professional look." -- John Mallinckrodt, The Claremont Colleges

"Looks beautiful in color!" -- Eric T. Lane, University of Tennessee - Chattanooga

"... the program does what is advertised, has quite clear and concise explanations of what one is seeing. Given the 'hot' nature of chaos these days I'll bet this proves to be a popular piece of software." -- Robert Lynch, King Fahd University, Saudi Arabia

"Thoroughly enjoyable set of programs" -- Byron Dieterle, University of New Mexico

"Works wonderfully - a real addition" -- Martin Keneger, University of Southern California

"Glad to see a program that will run on my Hercules board" -- Art Western, Rose-Hulman Institute of Technology

"Support of Hercules graphics is appreciated! ... Probably the best piece of software that I have seen out of the project!" -- Mark Horbatsch, York University, Toronto

"Beautifully done package. All of it worked as advertised." -- Ken Ford, Executive Director and CEO of the American Institute of Physics

"This is a marvelous piece of software. I spent far too much time enjoying it. I feel it could prove to be inspirational to a student who gets the false impression that physics is just a bunch of ugly equations. Sprott's programs show how beautiful equations can be!" -- Don C. Kelly, Miami (Ohio) University

"This is one of the best programs I have evaluated for Physics Academic Software so far. It performs very well, is intuitive to use, very informative and provides fantastic graphics. Good work!" -- W. T. Sobol, Winston-Salem, NC

"Congratulations! The best piece of work so far..." -- Dr. Karl Guitterer, Gronz University of Technology, Austria

"Overall, this was the best program I have examined." -- Henn Sooupaa, University of North Dakota

"Excellent program" -- Howard C. McAllister, University of Hawaii

"No difficulties. Good graphics, enticing program" -- Herb Waring, Miami, OK

"Fun program! Easy to use." -- Diane Grayson, University of Washington

"These are very good programs...the interface is pleasant and easy to use. A very nice collection." -- Jack Wilson

"Great! Very informative." -- Peter Layde, University of Wisconsin - Madison

"Very nice package. Every time I brought it up, I drew a crowd around my desk. Dr. Sprott seems to have a knack for putting together some very user-friendly packages that have a great deal of flexibility. I was very impressed with his earlier "Physics Demos" package and this one was even a bigger hit with my colleagues. I found everything to work as described in the manual, although one hardly needs it with the menus." -- Joseph G. Harrison, University of Alabama

"User friendly - easy use with mouse. Easy change from configuration space views to phase space views. Excellent parameter change mechanism." -- Anonymous reviewer for Educom 1990

"These phenomena can really be shown only in an animated presentation. Students are very interested in this. Very good! Very friendly, easy to use. Interesting subject matter. Wide variety and examples. Something for everyone, faculty and student alike. Runs on simple hardware. This is an example that shows the computer-as-learning-aid at its most useful. Sprott's package gives a delightful assortment of non-linear and chaotic demonstrations. The program runs easily, parameters are easy to change, and one has a choice of visual outputs. It is interesting to students and faculty on many levels." -- Anonymous reviewer for Educom 1990

"Education to date has left students believing that analytical solutions exist for most natural phenomena, i.e.: if we knew enough we could predict. Chaos implies that even simple systems cannot be predicted. The subject could not really be covered except in an abstract way without a computer. Very easy to use, very clean interface. Multiple views of various phenomena is excellent! Covers a straightforward graphical way. Gives real world examples of many of the phenomena. Turning the sound on adds an interesting sensation." -- Anonymous reviewer from Educom 1990

"The importance is obvious to almost all scientists today. Up-to-date, pleasing to the eye, consistent, easy to learn, attractive, exceptionally well-done interface, illustrates a new field." -- Anonymous reviewer from Educom 1990

"Chaos is one of the areas where students can begin to appreciate that much of nature is non-analytic. Author appears to have complete command of subject matter. User-friendly; requires no prior knowledge to start using the software. Excellent from human factors perspective. Extremely easy to use. Beautiful graphics. Very captivating--one can spend hours playing with the software. The beauty of chaos can only be illustrated with these kinds of simulations. Can be used (as a curiosity piece) by students/adults at any educational level." -- Anonymous reviewer from Educom 1990

"I do feel that the program is beautifully done, and I congratulate you on a nice piece of work. It is like a breath of fresh air, after some of the shoddy work that I have reviewed" -- Prof. Philip DiLavore, Indiana State University

"What is different about this particular program is its exceptional easy to use interface. The program is a joy to use. It takes no time at all to learn to use it. One feature that I particularly like is the way the Julia sets and Mandelbrot sets are drawn." -- Anonymous reviewer from Educom 1991

"I give this software very high marks. It is easy to use, looks very professional, and covers many (about 20) chaos topics. The selection of topics is good and they are, by and large, well presented. The user can adjust various parameters and see the graphical effects they lead to. There are useful choices of type of graphical demonstration, and some nice use of sound in some of the examples. The explanations are good. The software provides a good introduction to the field." -- Anonymous reviewer from Educom 1991

"Very good. Outstanding. This is very cool! You should have a lot of these. Awsome! Supersonic. The 3-D effect adds a lot to some of the graphs." -- Anonymous museum users