myphysicslab – help and faq
- why don't the simulations play in my browser?
make sure that you have java enabled in your browser. for internet explorer on windows go to "internet options", click the security tab, and make sure that "java permissions" are enabled. you also should enable "scripting of java applets".
in addition, you may need to get java software if you don't have java, or have an old version.
- why is the animation jerky?
some browser and operating system combinations don't give enough time to the applet to allow for smooth animation. one possible solution is to download the lab.jar file and then run the simulations directly outside of the browser. after downloading the lab.jar file, just double-click it. if java is installed, the simulations will start running. there is an additional menu item that lets you pick which simulation to run. (if double-clicking lab.jar doesn't work try typing at your command line: java -jar lab.jar). another thing to check is that you have the latest java software.
- how can i show the simulations to my class?
you can copy the applet onto your local computer hard disk. see the sections below on displaying simulations off-line and changing size of display.
- clicking the buttons doesn't do anything.
for the buttons outside of the java applet, make sure that "scripting of java applets" is enabled in your browser security preferences.
- the math symbols don't appear.
these symbols: − θ π ω √ ∫ ∑ ⁄
should look like this:
if the symbols don't appear, try changing the serif font or default font in your browser, by looking in tools or preferences. some fonts don't have all these special symbols. in some cases, choosing a different size of font may also help. there may be other browser settings needed to enable these html 4.0 character entity references. more info on how to configure your browser and fonts is at alan wood's unicode site.
- how do you display math on the web?
displaying math on web pages with html is challenging. there are many approaches. i have some notes on how to display math on the web that you can look at for ideas.
- is source code available for the simulations?
yes! just scroll down on this page for information about getting source code.
free source code
the java source code for the myphysicslab applet is available at www.myphysicslab.com/source/
. you should be able to download individual files there by right-clicking on a file. you can also try accessing that directory by anonymous ftp
the source code is covered by the gnu general public license
. using the gnu gpl ensures that all subsequent improved versions will be free software
. here free
rather than "no cost".
i would like to hear from anyone downloading, using, or improving the source code. send me a note
about what your interests are with the code. i would also appreciate if you could provide a link to www.myphysicslab.com
if you use the source code on your website or at your school.
simplified source code
a simplified text-only version
of the source code suitable for students to experiment with is available.
displaying simulations off-line
its easy to display the simulations when not connected to the internet. first download the lab.jar file
. after downloading the lab.jar
file, just double-click it. if java is installed, the simulations will start running. there is an additional menu item that lets you pick which simulation to run.
if double-clicking lab.jar
doesn't work (and you are sure that java is installed) try typing at your command line:
java -jar lab.jar
if you also want the web pages that go with the applet, you can download a copy of this website onto your computer for display off-line. it is accessible via anonymous ftp
. here are the steps to take:
- establish an ftp connection to ftp://www.myphysicslab.com.
- copy the files lab.jar (contains the java applet) and stylesheet2.css (used by all the .html files)
- copy whichever of the .html files you want.
- copy the /images/ subdirectory if desired. the images are not used by the java applet, they are only needed for images appearing in .html files.
- from within your browser, open the desired .html file on your hard disk.
changing size of display
if you need a larger display to fill the screen for a presentation, you should follow the instructions above
to get a copy onto your local hard disk. if you are double-clicking the lab.jar
file, then you can simply resize the window as desired.
if you have copied the .html
files, then use a text editor to modify the .html
file that shows the simulation of interest. the line to modify will be near the beginning and look something like this:
<applet code = "com.myphysicslab.simlab.lab.class" name="lab" archive="lab.jar"
codebase="." width=500 height=300>
you can change the width and height to whatever you need. then save the file and open it with your browser.