Progressive and Standing/Stationary Waves

In some waves the vibrations can be observed moving throughout the material but in others the vibrations/ disturbances can appear to be still or not present in the material; with these facts scientists were able to categorize waves based on these differing characteristics. These are:

1. Progressive Waves
2. Standing/Stationary Waves

Progressive Waves
Progressive waves are those waves having visible disturbances meaning the vibrations can be seen moving throughout the material.

Standing/Stationary Waves
Standing waves are produced when two waves interfere this results in an invisible disturbance though the wave is moving throughout the material. Standing waves consist of two different points known as nodes and antinodes.

Nodes: These are points in the wave that have zero energy and displacement.
Anti-Nodes: These are points in the wave that have the highest energy or amplitude.

The distance between two consecutive nodes or anti-nodes makes half a wavelength.

Waves formed from stringed and wind instruments are stationary waves. Open ends always have an antinode while closed ends have a node.

Stationary wave in Wind Tube