The sea surface motion is the superposition of numerous wave trains. Here one to four (linear) waves can be summed, traveling in the +x direction or the opposite direction. You can examine one, two, three, or four waves together by setting the appropriate wave heights to zero. The displayed quantities: Wavelength (L) and Speed (C) denote the characteristics of each wave. Pressing Reset will restore the default values. (Note: The plot region is not to scale with the depth.)

A variety of phenomena can be examined with this applet:

• Single wave trains: Found by zeroing the heights of the other three waves. The speed of the wave, C, can be determined by noting the time it takes a wave to traverse the entire screen.
• Wave groups: Very noticeable when two (or more) waves have nearly the same wave period. The group velocity can be determined empirically by timing the group over the distance.
• Standing wave systems: Occur when two waves have the same characteristics but are traveling in opposite directions.
• Wave groups reflecting from a wall: Use two waves to make a wave group (each wave with a slightly different period); then add two more waves with the opposite direction but otherwise the same characteristics.

The time step and domain length are taken from the properties of the first wave.