Animation of Wave Packet

This animation shows a traveling wave packet, representing the real part of the wave function of a free particle. The envelope of the wave packet moves with the group velocity. Individual waves within the envelope move with the phase velocity.

The program recognizes the following commands. The command may be executed by either clicking the button with the mouse (first column below) or by pressing a key (second column below). The mouse buttons may be removed from the screen by pressing the M key. Press M again to restore buttons.

stops Pause animation. Press stop again to resume animation.
restartr Puts wave packet at beginning. Press stop to resume animation.
velocityv Displays two vertical lines. One line moves with the speed of the group velocity. The other line moves with the speed of the phase velocity. Press velocity again to remove the two vertical lines.