Standing Wave Graphic
This graphic is from an Apple // program by Eric Lane. When I am teaching my unit on Quantum Mechanics, an important idea is that unlike particles, two waves can be at the same place at the same time. This graphic shows the two component waves (orange and blue) and the resultant white wave.

There are places on the string where the two waves constantly cancel (destructive interference). The ends of the graphic are a great place to see this. Note that there is zero amplitude at these points.

There are also places where the two waves always pull the string up together or pull the string down together (constructive interference). This results in maximum amplitude.

How we did it:
  • We ran the Eric Lane program on an Apple //e computer connected to a Macintosh with AV (audio visual) inputs.
  • We captured this section of the program as a movie.
  • Using shareware (GIF Builder) we turned the movie into an animated GIF file. The program allowed us to trim the picture down to the essential part of the screen we were interested in.
  • The animation was very dim, however, so we separated the animation file into 54 single GIF files. Each file was brightened using Adobe Photoshop.
  • The individual files were put back together to make this GIF. [I am CERTAIN there is a better/easier way.]