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Using the Physics Web Modules: How to

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Both students and faculty here at VCU and anywhere else on the World Wide Web are welcome to use these materials for educational purposes. (Certain restrictions on for-profit uses are detailed in the Copyright section.).

For students, I have some hints about how to use these notes to study physics. For teachers, I have information about how to build a web-based physics course by editing this one, linking to this one, or swiping stuff from this one.

This web-site is designed, for the most part, to be navigated by clicking on links and not by using the scroll bars. The page which you are reading now is designed to be read either way. However, most of the pages actually consist of linked "screens" which may appear in the same file separated by vast amounts of "white space" so that no conceivable display resolution could show them simultaneously. Because these screens are linked into a nonlinear hypertext, they make very little sense if you try to read them by scrolling down the display.

The general rule throughout this site is that return links appear at the bottom of each page. Sometimes several return links are listed, in which case, the one closest to the left side of the page leads to the previous level. Long scrollable pages such as this one also have return links at the top.

Links to all of the main parts of this web-site can be found on the Navigation Page. To get to the Navigation page, click on the button wherever it appears. There, you will find links to the current daytime and evening course syllabi, lists of quiz questions asked in each section, links to all past course syllabi and quiz question lists, a link to a list of important formulas, and links to all of the individual modules in the course.

If you are a student in this course, then you can find what you need by following the links from the course syllabus. Students in the daytime section can get to their syllabus by clicking on the course home page button or by typing in the URL

If you are a faculty member building a course web-site and you want to see what is available here, go to the navigation page () and use the pull-down menu to select one of over a hundred modules. If your browser cannot handle the JavaScript pull-down menu, there is also a complete hyperlinked outline which can be used to select modules by topic. At the bottom of the opening screen of each module, you will find a navigation button which can take you back to the navigation page when you are through looking at a module.

One way to get help is to send an e-mail directly to me at rgowdy@saturn.vcu.edu. A somewhat better way is to post your question in the Help! Forum where everyone in the class can see and respond to it. I will monitor the help forum and will add correction statements to any posts that are wrong or potentially misleading.

You can get to the Help! Forum by clicking on the symbol wherever it appears. The forum runs in its own separate browser window so that you can refer to the web-notes while you formulate your questions.

Plan to spend an hour before each class, going over the material which will be covered. That is a good idea in any class but is especially useful in this one where you are asked quiz questions throughout each lecture. Your in-class quiz scores count toward your final grade. By going to the web ahead of time you can preview all of the questions which might be asked and see explanations of the answers. Why would you not do this?

Your course home page ( or ) contains an outline of the topics which will be covered in the course as well as a tentative schedule. Start with "Topic Questions" and follow the outline links until you get to the modules which were covered in the previous class. Move on to the next module and click on the link to "Study Questions". There will be several subtopics listed, each linked to a different cluster of questions. I am adding questions as fast as I can but you will still find many modules in which there is only one question per subtopic. In the modules that I have been able to update, you will find several different questions for each subtopic. For example, in module 8 you will find two different questions 08.1N and 08.1A, each available in two different versions. The versions, such as 08.1Na and 08.1Nb, differ only in the order of the possible answers. Choose a question and notice that each of the answers is a link. Click on the answer that you want and get a screen showing the question with your answer and an explanation of why that answer is right or wrong.

If the answers are not making sense to you, notice the left-arrow labeled "What this question is about" and click on it to get to a more complete explanation as well as links to examples. You could, of course, go through these explanations and examples first and then try the questions. For folks who like to see examples first and then the explanations, the opening screen of each module provides a direct link to the examples and there is a link from each example to what it is an example of. We all have different ways of operating. I am told that there are even some folks who read their VCR instruction manuals before trying to operate their VCRs. The modules are set up to let you roam around in whatever way works for you.

Guard against memorizing numbers and letters such as "the answer to 08.1Aa is D". First of all, that information will not be useful on the exams which comprise the largest amount of your grade in the course. Second, I have been known to hide alternate versions of the quiz questions and switch the links to the alternate versions a few minutes before class.

The web-notes are basically an outline and consist of images and simple statements that are intended to focus your attention during class. They cannot replace your textbook, which contains complete explanations as well as many more examples and worked problems and is much easier to read at the beach than a laptop computer would be. The only difficulty with using the textbook is figuring out where to find the material covered in a given web-module. A Module-page map is provided for this purpose. This map tells you which pages of the last two editions of the textbook cover the material in each web-module.

An exam measures your ability to remember the right thing at the right time. It measures your ability to associate or link one idea with another so that you can associate each question with the information that you need to get the answer. If you have not constructed these mental links you can understand and even memorize everything in a course and still flunk all of the exams in that course.

If you have been attending class and doing OK on the quizzes, then you are understanding the material. Now comes the hard part which you can only do by yourself (or possibly with a friend or two).

1. Reconcile the material with what you already know. If what you already know is wrong, then you need to deal with that.

2. Review the material so that you get it all in your head at once. Your mind will automatically start organizing it for you if you just get it all in there.

3. Test yourself on the material by pulling up quiz questions at random or by having a friend ask you questions or by taking a review exam (which I will provide before each exam). Whenever you can't answer a question, go back and review that material again.

The key point here is that learning is something that you do and not something that is done to you. You must be active. You cannot learn by only listening. You learn a thing when you talk about it. If you are an introverted type, then you are pretty good at talking to yourself and can study alone so long as you remember to keep that internal conversation going. Otherwise, find someone to talk to. Simply telling someone what you are having trouble with will often solve your problem even if the person that you are talking to is as confused as you are.

You are welcome to download files from this site and adapt them to your purposes (see the Copyright section). However, you should be aware of some potential problems. Some web publishing programs such as MicroSoft FrontPage insist on rewriting HTML code when they import it. Many of the HTML files from this site will fail when they are rewritten in this way.

The problem arises because the basic design of the web modules was set early in 1995. Back in those early days of the web, Netscape was in version 1.0 and many computers were still running Mosaic. Backgrounds were grey. There were no tables and font tags did not always do what you expected. Thus the notes were hand coded in a small subset of HTML to increase the chance that they would work in all the various browsers of that era. The biggest problem is that header tags were used instead of font tags. The trouble with this approach is that present HTML coding standards insist that a header must be a single logical object. If an entire page with several paragraphs is declared to be a header, an editor such as FrontPage will apply the header tags only to the first paragraph. Other problems arise because I have tweaked the way in which pages display by nesting tags in a certain order. Very often modern HTML editors will "standardize" the nesting of tags, thus destroying some of my effects.

I am working to standardize the HTML coding of these pages but it will take a long time (There are over a thousand files.) Until I finish the job, you will have to do what I do when I import a page into a modern HTML editor. Bring up your browser and load the unedited file into it before you start your HTML editor. Run the editor and the browser in side-by-side windows. The editor will give you a WYSIWYG display which looks only a little like what you see in the browser. Change the fonts until they look right. You will still have some weird stuff to deal with, such as link-underlines which extend farther than they should. Most of these remaining problems are caused by tags which are nested in the wrong order and can be fixed by going into a direct HTML editing mode.

As I update the HTML coding I am also changing the background colors. Expect problems whenever you try to edit a page that uses the old-style grey background.

This web-site is designed to be a shared resource for teaching several different physics courses. The basic shared unit is the web-module. Each module is built around a single root html file which is always named s.htm. The simplest way to incorporate a module into your own web-site is to provide a link to the root module. For example, a link to the URL http://saturn.vcu.edu/~rgowdy/mod/005/s.htm#state would display the module on Galileo. There are many other files in the 005 folder and you might be tempted to link to one of them. If you do that, please be aware that I am re-designing the modules constantly and have re-organized the file structure several times already. Only the s.htm file is guaranteed to remain the same in each module.

A difficulty with simply linking to a module is that the return links from that module will not point to your syllabus. Because a student is likely to follow dozens of links within the module before trying to exit from it, the back button and the history list are not very useful. One extremely simple way to deal with the difficulty is to construct your link so that it will launch a separate window. When a student finishes browsing the module, closing the window will uncover your syllabus again.

For faculty members here at VCU, there is a more elegant way to incorporate modules into your course web-syllabus. Here are the steps to follow:

1. Create a folder named ctrl within the folder where you keep your web-syllabus. For example, my daytime PHY101 course home page is at the URL
   http://saturn.vcu.edu/~rgowdy/p101dcur/
   so I would create the folder http://saturn.vcu.edu/~rgowdy/p101dcur/ctrl.

2. For each module that you intend to use, create a control file - an html file named m[nnn].htm where [nnn] is the module number and place it in the ctrl folder. This file should display whatever you want students to see when they return from that module and should have links back into the appropriate part of your course syllabus. For example, if you are using the Galileo module 005, then you would create a file ctrl/m005.htm which might contain a list of links to modules, including 005, and a return link to your course outline.

3. (VCU Faculty only!) Send the URL for your control file folder to rgowdy@saturn.vcu.edu along with your course name and a list of the modules which you intend to use. I will edit the root files for those modules so that they have return links pointing to your control files.

4. If you decide to rearrange your course outline so that modules are grouped differently, just edit your own control files to reflect the new grouping. I do not need to know about it.

I am frequently asked about how to download and use the animations which are found in these modules. All of the animations are simple GIF89A format files, so it is really easy to swipe them and incorporate them into your own web pages (after checking out the Copyright info, of course).

Just in case there is someone out there who does not know how to download an image, here is what works in Netscape Communicator running on a PC:

1. Right-click on the image and choose "save image as".
2. Choose the folder where you want the image file to live and "save" it.
3. Use your HTML editor to insert the image into your page.
4. When you display your page in any recent browser, the animation will run.

The animations used in these modules were created using Canvas to draw individual pictures which were exported in GIF format and then imported into a simple animation program (Egor Animator) which combined them into a single GIF file. For editing and rescaling the images, you need to use the original Canvas format files. I can supply these originals upon request.