Standing Waves can resonate in a pipe. The resonance occurs in an open-closed pipe when an odd integer number of quarter wavelengths fit exactly in the length of the cavity of the pipe. This animation illustrates what happens when a plunger is used to "scan" the effective length of a pipe driven by a tuning fork. Three different cases are shown for a set of increasing frequencies.
The title says it all: this blog features physics videos found everywhere on the web: animations, demonstrations, lectures, documentaries.