You could try cloning this Physlet and running it locally...but don't try it quite yet. It won't work unless you also have downloaded the appropriate jar (java archive) files, containing all the java code to run the Physlet, from Davidson College.
To do this go the Physlets site at Davidson College and select the "Download" link, and then select the "JAR FILES" link.
Right-click on the Animator4_.jar file and save it to a folder called "classes" on your own computer (you'll probably need to create a new folder called "classes" for this). Repeat the process for the STools4.jar file, also saving it to the "classes" folder.
Now clone this Physlet file by right-clicking somewhere in this browser window (but not in the Physlet area), selecting "View Source", and saving the file in a folder at the same level in the directory structure as the classes folder. For instance, you could create a new "physlets" folder on your computer at the same level as the "classes" folder and save this Physlet file there.
Now, the moment of truth. Open up a new browser window, and from the File menu select "Open" to open the file you just saved in the "physlets" folder (or whatever folder you put it in!). If everything is set up properly you should see a copy of this Physlet in the new browser window.
Note that the "classes" folder and your "physlets" folder don't necessarily have to be at the same level in your computer's directory structure, but if they're not you will need to modify what's in the codebase section of the Physlets file so the browser knows where to look to find the jar files.