Support

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 notify us by email at the following address: phethelp@colorado.edu.

Simulations with Sound

Simulations that use sound can be unstable when run on computers using old device driver software. If you are encountering crashes or other undesirable behavior with any of our simulations that use sound, we advise updating your sound drivers, as this may solve the problem. For assistance with updating your sound drivers, contact your computer vendor or audio hardware manufacturer. Contact us at phethelp@colorado.edu if you continue to encounter difficulty.

Screen Resolution

PhET simulations work best at a screen resolution of 1024 x 768 pixels. (Some of them are written so that they cannot be resized.) At lower resolution (e.g. 800 x 600), all the controls may not fit on your screen. At higher resolution (e.g. 1280 x 1024), you may not be able to make the simulation fill the whole screen, or if you do, it may slow down performance. To change your screen resolution, follow the directions below:

Windows:

  • From Start menu, click on “Control Panel.”
  • Double click on “Display” icon.
  • Select the “Settings” tab.
  • Use the “Screen resolution” slider to select a resolution and click “OK.”

Macintosh:

  • Open the System Preferences (either from the Dock or from the Apple menu).
  • Open the Displays Panel and choose the Display tab.
  • On the left of the Displays tab you can select one of the Resolutions from the list.
  • Quit or close the System Preferences when done.

System Requirements

Windows™ Systems

  • Intel Pentium processor
  • Microsoft Windows 98SE/2000/XP
  • 256MB RAM minimum
  • Approximately 50MB available disk space (for full installation)
  • 1024x768 screen resolution or better
  • Sun Java 1.4.2_10 or later
  • Macromedia Flash 7 or later
  • Microsoft Internet Explorer 5.5 or later, Firefox 1.5 or later

Macintosh™ Systems

  • G3, G4, G5 or Intel processor
  • OS 10.3.9 or later
  • 256MB RAM minimum
  • Approximately 40 MB available disk space (for full installation)
  • 1024x768 screen resolution or better
  • Apple Java 1.4.2_09 or later
  • Macromedia Flash 7 or later
  • Safari 1.3 or later, Firefox 1.5 or later

Linux Systems

  • Intel Pentium processor
  • 256MB RAM minimum
  • Approximately 40 MB disk space (for full installation)
  • 1024x768 screen resolution or better
  • Sun Java 1.4.2_10 or later
  • Macromedia Flash 7 or later
  • Firefox 1.5 or later

Support Software

Some of our simulations use Java, and some use Macromedia Flash. Both of these are available as free downloads, and our downloadable installer includes Java for those who need it.

Java

To run the simulations that have atag under them, you must have Java version 1.4 or higher installed on your computer. You can obtain the free downloads by clicking on the button below:

Note for Netscape Users

After you have installed Java Web Start, you will need to close and re-open your browser for Java Web Start to work.

Java Web Start vs Java Applets

We use Java Web Start technology rather than Java Applets. Java Web Start, which is a free mechanism from Sun, is a more robust way of launching Java programs over the Web than applets. If you have had problems running applets in the past, you may well find that Java Web Start works much better. If you should have any problems, we will be happy to help you solve them. Just send us email (Click Here).

Flash

To run the simulations that have atag under them, you must have Flash 7 or newer installed on your computer. You can obtain the free support software required for them by clicking here. If you are unsure if you have this software, we can check for you if you click here.

If you get a blank window when you try to launch a flash simulation, you probably need a new version of the Flash player, available for free at Adobe.

Note: Older versions of the Flash™ Player can cause problems. If you receive an error such as this:

You should download a current version of the Flash™ Player here.

Note for Macintosh™ Users

Please note that some of our Java-based simulations will run slowly on Macintosh™ computer systems. Some simulations may not run correctly on Macintosh systems. These simulations can be identified by thetag below them. If you encounter further problems, please contact us with the relevant details. You should also heck the minimum system requirements.

Note for Windows 2000™ Users

Some Windows 2000™ systems have been reported to lack part of the necessary Java configuration. These systems will typically start our Flash-based simulations reliably, but will appear to do nothing when launching our Java-based simulations.

  1. To resolve this situation, please perform the following steps:
  2. From the desktop or start menu, open "My Computer"
  3. Click on the "Folder Options" item in the "Tools" menu
  4. Click on the "File Types" tab at the top of the window that appears
  5. Locate "JNLP" in the "extensions" column, and click once on it to select the item
  6. Click on the "change" button
  7. When asked to choose which program to use to open JNLP files, select "Browse"
  8. Locate the program "javaws" or "javaws.exe" in your Java installation folder (typically "C:\Program Files\Java\j2re1.xxxx\javaws", where "xxxx" is a series of numbers indicating the software version; choose the latest version)
  9. Select the program file and then click "Open" to use the "javaws" program to open JNLP files.

Java-based simulations should now function properly. Please contact us by email at phethelp@colorado.edu if you have any further difficulties.

Note regarding security settings in Internet Explorer

Some installations of Internet Explorer, particularly under Windows XP SP2, have default security settings which can impede some aspects of how your locally installed PhET interface functions. For the best user experience while using our simulations installed on your computer, we recommend following the steps below:

  • In Internet Explorer on your local workstation, choose Tools > Internet Options.
  • Choose the Advanced tab, then scroll to the Security section.
  • Enable "Allow active content to run in files on my computer".
  • Choose OK.

Note regarding QuickTime™ and Flash™ compatibility

Possible Compatibility Problem

It has come to our attention that some of our users are unable to use our Flash-based simulations due to a compatibility issue between Apple Computer's QuickTime™ and the Flash™ player. Some users have reported that uninstalling QuickTime resolves the issue.

We are aware that this is not an acceptable solution and are working to resolve this issue. If you are experiencing this problem, please contact us at at phethelp@colorasdo.edu and check back here for more information regularly.

Performance Issues

On some laptop computers, simulations may appear to run much slower than anticipated and/or exhibit unexpected graphics problems. This may be due to power management settings that affect how the computer's graphics system runs and can be corrected by either a) changing the computer's power management configuration, or b) using the laptop computer while plugged in to an AC power source.

Many laptop computers are configured to reduce the amount of battery power used by the graphics/video system while the computer is running on battery power. If you must use the laptop while it is not plugged in, we suggest changing your computer's power management settings to "maximize performance" while unplugged. This should ensure that the graphics system runs at its peak speed. The location of this setting varies from one manufacturer to the next and we suggest contacting your computer vendor if you have difficulty locating it. Please contact us at phethelp@colorado.edu if you continue to encounter problems.

Translating PhET Simulations to Other Languages

Note: Viewing the documents listed here requires Internet access.

The PhET simulations have been written so that they are easily translated to languages other than English. The process requires no programming skills, and is described in the following two documents: