coupled oscillator animation Note the energy transfer (visible as motion) from one block to
the other and back. In a piano or guitar the string transmits energy to the sound board (or top and bottom plates). However the energy is not sent back to the string but rather
transfered to the air so that we hear it.
natural modes Note that these modes differ slightly from the ones we discussed in that
the end masses are attached to walls by springs. Nevertheless, this may be helpful to see the oscillations instead of just snapshots at half-period intervals.
natural modes of a string
drumhead animations
animations of a square drumhead
animation of longitudinal standing wave Hopefully this will clarify displacement vs. pressure
nodes.
Some relevant (and loosely relevant) applets (you get to play with the animation)
natural modes of a string
natural modes of a square membrane
natural modes of a circular membrane
various cases for bars (free and clamped)
diffraction and interference
spectra, fourier series - there's a lot here, but it's very worthwhile to play with