The work of a curious fellow

Conservation of Momentum Pendulum Phase Space

.: Knowledge and understanding

The longest journey has to start somewhere and somewhen. If not here, where? If not now, when?

Hi there. My name is James D. Jones and you are apparently someone who wants to understand the world around you. Please excuse me for getting all philosophical on you in this introduction. It has been my experience that having had this sort of discussion helps keep me focused when the going gets tough. The objective, as it turns out, is to drain the swamp. If you at times feel that I have lead you in amongst the alligators, then think back to the following few paragraphs.

Understanding is different from knowledge.

In a preceding paragraph I used the word "understand". Let's make a distinction between understanding and knowledge. Knowledge involves facts. I may know that the Earth is closer to the Sun at some times than it is at others. Understanding involves patterns among bits of knowledge. I may understand that the conservation of angular momentum in a central force guarantees that all orbiting objects cover equal areas of their orbit plane in equal intervals of time. Knowledge allows me to answer a single question. Understanding allows me to answer all the questions of a certain sort.

Unfortunately understanding is not something that can be given to you. If it were, than everyone would have it. Real understanding comes from making internal mental connections among bits of knowledge that we pick up in a lifetime of learning. At some point a pattern emerges from the connected bits of knowledge and understanding begins. For most folks this understanding provides a framework into which new bits of knowledge may be placed. It helps us make sense of the world and organize our thinking. For a few talented people, this understanding allows them to predict new facts that would fit the pattern of the universe. Then they can go looking for those facts to further validate their understanding.

There are levels of understanding also. We may accumulate a number of facts related to physics, for example, and after a certain amount of playing with them, arrive at some understanding of the subject. It is like finding a little island of understanding in the swamp of ignorance. Then later we may study chemistry, accumulating some facts in that area and discover another island of understanding which gives structure to the chemistry knowledge. Likewise with biology, electrical engineering and so on and so forth. Then if you are very persistent or talented, you may find that you begin to actually drain the swamp of ignorance, revealing previously submerged connections of understanding among the islands. People who have gone before you may tell you that these connections exist but until you drain your own personal swamp of ignorance you cannot really see that it is so.

As you read the words I have written, try to really understand the topic. This is not easy to do if you are under the pressure of a short timeframe and looming exams. That is the advantage of the sort of learning venue we have here. There is no end date for this course, no exams and no cost. The absence of pressure does require a certain discipline on the part of the student. You have to dedicate some of your most valuable resource, your time. I am available to answer questions by email and I look forward to interacting with students. I will probably not do your homework for you but may have some words of advice to get you over a sticky point. I take great satisfaction in witnessing the "Ah ha! I get it." moments that a student experiences.

The ideal time to work through this course is during the summer between high school and college. If you read the text and play with the displays included in this course, you will enter your freshman physics course in the fall with a distinct advantage over most of your classmates. Nothing succeeds like success and success in freshman physics can set the tone for your whole college career. Your classmates will be coming to you for help, which is a good thing. You will find that you really begin to understand when you have to explain something to someone else.


.: The nature of physics

What is physics?

The study of the natural universe, as opposed to the supernatural I guess, was called in ancient times, natural philosophy. As the knowledge and understanding of the natural universe grew, people had to specialize, and parts of natural philosophy were separated out and given different names. Subjects like chemistry, astronomy, geology and so on got a life of their own. Today there is a name for those parts of natural philosophy that were left over, not captured exclusively in one of the other named sciences. The Greek word for "natural" in physikos so in recognition of the ancient Greek origins of the subject, it is now called physics.

Physics is unique in its central location among the islands of understanding in the swamp of ignorance. Because all the other sciences were extracted from it, physics is most visibly connected to all the other islands of understanding. Also because physics is the "everything else" subject, it is not very easy to define. In any event physics is the customary starting point for serious students of the sciences and engineering, so here we are.

Physics is not easy.

Introductory physics has gotten a reputation in recent times as being a difficult subject. I think there are a few reasons for this and we may as well get to them right up front. First of all it is not easy. Physics requires a level of abstraction from the student that may come as a shock to folks making the transition from high school to college. Secondly, introductory physics is taught in a language that is not spoken in the home of any of the students... mathematics. Thirdly, introductory physics being common to many sciences tends to be taught to large groups at a rapid pace so as to get it out of the way early in a student's career. Finally, many schools do little to ease the student's burden, using introductory physics to wash out students with only average aptitude for scientific thinking so as to have manageable numbers of students in the higher level courses. The upshot of all this is that the average student of introductory physics feels like he or she is getting a drink from a fire hose. It tends to be a bit overwhelming.

The order of proceeding

For as long as physics has been taught as a distinct subject, it has been taught sort of in chronological order of the discovery of the concepts. This has the advantage that the concepts were discovered in the order of intuition. Those ideas that were most intuitive were naturally first to be recognized. Lately I have been wondering if that is the most efficient approach. Since from the student's point of view it is all new anyway, perhaps there would be a benefit in starting with the most profound principles and working from there. This particular notion is presently only half-baked in my mind so we will proceed from Newton onwards as is the custom.

With that in mind, I recommend that beginning students work with the course that is named, without much imagination, Physics-1. There are two ways to go. My recommendation is that you download the free program and install it on your computer. The Physics-1 program has been tested in Windows XP, Win 7 32 bit and 64 bit and Win 8 32 bit and 64 bit. The installation program in which it is wrapped will match the installation to your operating system. The installed size of the program on the hard drive is about 2 megabytes. Before running the installation file, see the installation instructions for detailed suggestions on the steps to follow in installation. Click on the Physics-1 Install link and click on "Run". Depending on the security system settings you have, you will probably have to, in spite of perhaps multiple dire warnings, "Allow" the program to access your computer.

I have made available an online version that lacks some of the convenience and power of the native version, running Java applets rather than native code. The contents of the course is the same in either version.

Unfortunately the Oracle Corporation, which now manages the Java programming language, in 2014 implemented a security change that prevents applets that have been running without problems for decades from working. I have decided to leave the online version available because the text gives you a good idea of the contents of the downloadable program. You will not be able to use the dynamic illustrations until Oracle fixes this issue.

Both versions were last updated several years ago when M Casco Associates was selling the course. You may see some reference to the commercial operation in the text. Someday I may do a re-write to clean that up but since I retired I have been too busy to get to it yet. Just click on the online version link above to get started.

.: -----For folks with the fundamentals of physics well in hand-----

In the "Order of proceeding" section above, I mentioned that there might be a better way to approach the order in which topics are covered in teaching physics. As a first whack at that in a you might look at the program I wrote called Physics-T. It was written with the idea of helping the transition from basic physics to the subjects normally reserved for the more experienced students. It occurs to me that maybe one could start with something like Physics-T and cover Newton as an easy approximation to the more precise theories.

I am sure Physics_T would require some re-writing to accommodate beginning students (and a better name) but perhaps starting there, or maybe even better as a starting point would be the principle of maximal aging that underlies the least action idea. The Physics-T program requires one of the 32 bit Windows operating systems. The installed size of the program on the hard drive is about 2 megabytes. Before running the installation file, see the installation instructions for detailed suggestions on the steps to follow in installation. Click on the Physics_T Install link and click on "Run". Depending on the security system settings you have, you will probably have to, in spite of perhaps multiple dire warnings, "Allow" the program to access your computer.

When you start Physics-T, go to the "Open" menu item and open the "Introduction" file. That will explain how to proceed.

If any readers have an opinion on this I would appreciate an email. As things stand now, re-writing Physics-T is kind of low on my list.