Fowler's Physics Applets

This is a mirror site of the original!!!
Michael Fowler - University of Virginia Physics

These are a few applets I use to teach classes. My graduate students and I have written all the applets shown below. I collect them here because others may find them useful outside the scope of the lectures I provide on the web. They are also listed in major directories. Please feel free to link to any of them or download their source code. If you have suggestions or want to make modifications, I ask that you contact me at Those who need ask further copyright questions may read conditions for use.

Newton's Cannon - Relevant lecture for Physics 109 Galileo and Einstein

Newton's Principia suggested that if you fire a cannon from a high mountain it could fall, circle the earth, or fly away depending on how hard it was fired. While Newton may have approved the use of his drawing from the Principia, he may not have appreciated a cannon that sounds like a squeaky toy.
Rutherford scattering from a Thomson Atom and from a Nuclear Atom - Relevant Lecture for Physics 252 Modern Physics

Watch alpha particles scatter from atomic nucleii. These applets compare the Physics of two competing theories in 1910 for distribution of charge in an atom.

Group Velocity and Phase Velocity

Change the group and phase velocities of interfering sine waves. This is an economical but useful demonstration. Relevant Lecture for Physics 252 Modern Physics.

The following applets are in Java 1.1

Browsers older than Netscape 4.05 or Internet Explorer 4.0 will claim they cannot load these applets because they use the newer version of Java. It was simply more expedient to program with the revised Java. I apologize for the inconvenience.
Projectile Motion - Physics 581 Physics for High School Teachers

Shoot a cannon to see how high and far the ball flies. The applet uses real units and physical values to compare with calculations.

Einstein's Explanation of Brownian Motion - Physics 581 Physics for High School Teachers

This applet shows how atomic velocities cause the Brownian Motion of a dust particle. In one panel a small ball jitters. In the next, we see that it jitters because many smaller balls bat it rapidly about.

One-dimensional one-atom classical gas - Physics 581 Physics for High School Teachers

This applet describes a single atom gas moving in one dimension. It accelerates or decelerates only through classical collisions with the moving piston on its container. This alone is enough to explain why the gas gets warm when it is compressed and cool when expanded.

Two-dimensional collisions - Physics 581 Physics for High School Teachers

One ball strikes another. Change relative masses, initial velocity, and angle of the collision. Watch it in the center of mass and lab frame. It makes the collision angles very clear, and the controls are sort of fun.