In physics a standing wave is a uniform and relatively stable wave pattern of energy that doesn’t travel through a medium. Put differently, each point on the standing wave has a constant amplitude.
By way of example, imagine a long skipping rope extended on a smooth surface and held by two people at either end. When wiggled left to right by one person at a precise frequency, this particular type of wave differs in that its waveform (the height and shape of the curve) doesn’t move down the rope but remains stable, forming a uniform pattern.
This phenomenon can occur because the medium is moving in the opposite direction to the wave, or it can arise in a stationary medium as a result of interference between two waves traveling in opposite directions. The most common cause of standing waves is the phenomenon of resonance, in which standing waves occur inside a resonator due to interference between waves reflected back and forth at the resonator’s resonant frequency.
Erwin Schrödinger argued that all particles of matter are in fact standing waves of energy.
The implications of his theory are profound. It suggests that so-called matter within the universe isn’t really solid. We merely perceive it as solid through our senses and minds.