Understanding Standing Wave Diagrams

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A medium is moving when a standing wave is present on it. Of course, non-animated, or static, pictures can not capture this movement. This Flash animation is meant to help you relate the actual movement of the standing waveform to the shape of a non-moving diagram which is normally used to represent the standing wave.

Flash

This animation shows several harmonics for a standing wave on a medium fixed at both ends. Use the arrow buttons to step through the animation and read the other notes below.

Actually, the standing waveforms in these illustrations are drawn a bit too round, but the animation does allow you to see how the shape of a standing wave can be represented by drawing only the extremes of the motion. Such a diagram is said to illustrate the envelope of the wave.

The links below contain animations which more realistically demonstrate the actual forms of standing waves.

As you page through the above animation be sure to notice the meaning of the terms 'antinode' and 'node'.

An antinode in a standing wave is the region where the medium is in motion. The locations of the antinodes do not change as the standing wave vibrates, and thus the name 'standing'.

A node is a spot on a standing wave where the medium does not move. This may seem unusual at first. However, there are places along the medium which are motionless as the standing wave oscillates. The locations of these nodal points do not change as the standing wave vibrates.

 

The following are links to animations that more truthfully present the wave forms. Diagrams for several types of standing waves are included.

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