Here's why:

* Standing waves are formed by the interference of two waves traveling in opposite directions with the same frequency and amplitude.

* Nodes are points along the standing wave where the amplitude is always zero. This means the medium at those points remains stationary.

* Antinodes are points along the standing wave where the amplitude is maximum, and the medium oscillates with the largest displacement.

Think of a vibrating guitar string. The string appears to vibrate in place, with fixed points (nodes) at the ends and points of maximum vibration (antinodes) in between. This is a standing wave!