Standing Wave Modes in Sound Tubes

Standing wave modes in sound tubes depend on the boundary conditions at the ends of the tube. These boundary conditions describe how the air particles can move where the tube is open or closed. They set the pattern the standing wave must follow.

For a tube that is open at one end and closed at th...

Consider air trapped inside a tube that is open at one end and closed at the other. If a wave impinges on it, it reflects, producing standing waves.

The boundary conditions are antinodes at the open end, where air molecules are free to vibrate, and nodes at the closed end, where they are not.

If both ends were closed, the first pos...