Transcription: Under the right conditions, a slinky can be an excellent example of a longitudinal wave. Notice as the slinky is being shaken back and forth, it clumps together and pulls apart. Those are the oscillations of the wave. The wave's also traveling in the same direction, however. So in this case, the wave's propagation is parallel to the oscillation of the medium, and that makes it a longitudinal wave.
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