This page will help you solve some of the problems people commonly have running our programs. If you can't solve your problem here, please contact one of the instructors.
You must have either Java Web Start 1.2 (recommended) or support for Java version 1.4 applets installed on your computer. If you'd like to know more about this, see the section below. (Macintosh users, see "Note for Macintosh Users", below.)
After you have installed Java Web Start, you will need to close and re-open your browser for Java Web Start to work.
Mac OS 10.2 or higher is needed to run our Java programs. Our experience is there are bugs in the the Mac Java Virtual Machine for Java 1.4 that prevent several of our simulations from running properly, or running at all. You mileage mayvary...
There are two kinds of programs at this site: Java Web Start enabled programs, and Java applets. Each program has a functionally equivalent version of the other kind.
Java Web start is a technology for running Java programs on your computer that you download from a web site such as PhET. As with applets (see below) the downloading happens automatically. But in contrast to applets, the program will only be downloaded if there is a newer version on the PhET site than the one on your computer. This also happens automatically, without any work on your part. Since the program does not have to be downloaded every time you run it, as with a applet, this is usually a more efficient way to go.
Another advantage of Java Web Start is that you are less likely to run into quirky computer-specific problems that you will with an applet.
The downside is that you must first download the Java Web Start package from Sun Microsystems. It is free, but is a somewhat larger download than you need to run the applets. On the good side, you only have to do it once.
To set up your computer to run the Java Web Start programs, click on the following link and follow the instructions for your particular computer set up.
- Information on Java Web Start
- Java Web Start installation for Windows
- Java Web Start intallation for other platforms (Note: Select a download package from the JRE column)
These programs are simple to run, but may be more finicky on some computers. To run them you must have Java 1.4 on your computer, and your web browser must be hooked up to use it. If you have set up your computer to run Java Web Start (see above), you are also good to go with the applets.
To set up your computer to run the applets (if you have not already set it up to run Java Web Start), click on the following link and follow the instructions for your particular computer set up.