With the new Java update (51) from Oracle on January 14, 2014, Physlets will not run without an additional change to the Java security settings.
On Macintosh OSX or Windows
Update to Java 7 update 51
Open the Java Control Panel
on Windows: Start/Control Panels/Java
on OSX: Settings/Java
Select the Security tab
Set the security to Medium on the slider.
Restart your browser (if it is open).
Physlets will now run again. A different approach is to use the new feature of the Exception Site List in the Security tab of the Java Control Panel. Simply add the URL of the sites you want special access to, like http://www.compdare.org. This approach only reduces the security level for sites you specify.
In order to provide a more detailed description of how to change your security settings in Java, here is a zip file with two PDF files that you can use and distribute: a How-To for Windows and a How-To for Macintosh.
**These files now have the proper URL to the latest Java on the Oracle site**
