This java applet shows the "Superposition Principle of wave"

When two or more wave moving through the same region of space,

waves will superimpose and produce a well-defined combined effect.

Wave maintain their integrity upon overlapping (without themselves being permanently changed).

Blue colored wave + green colored wave ==> red colored wave

Blue wave moving toward right,(with fixed frequency f)

Press the -/+ button: change the direction of green wave.

two waves with same frequency and amplitude but opposite direction ==> standarding wave.

What if two wave with different amplitude?

TextField input:

Wavelength: enter wavelength λ for blue/yellow waves,

Frequency: enter frequency f for blue/yellow waves,

Wave is not necessary moves with the same speed.

We can calculate wave speed v = f*λ

Waves with two different wavelength produce beats phenomenon. (sample GIF picture)

Change parameters with mouse

Change phase between two waves:

Move mouse near the center line, click mouse button and drag it left or right

Change amplitude for each wave

Move mouse near the highest point of wave, click mouse button and drag it up and down.

Suspend the animation: click the mouse button.

click left mouse button	The animation resumes when the mouse button is released
click right mouse button	The animation resumes when click mouse button again

Click mouse button twice quickly to change the time scale:

Click left mouse button: slow down by a factor of 1.5

Click right mouse button: faster by a factor of 1.5

Your comments/suggestions are highly appreciated. My E-mail hwang@phy03.phy.ntnu.edu.tw

Author：Fu-Kwun Hwang Dept. of physics  National Taiwan Normal University