I'm learning bass guitar. Like all stringed instruments, the strings are fixed at each end. When you pluck the string, you create a wave on the string that travels along the string and reflects off the far fixed it. It crashes into the bits of the wave that have not yet arrived. If you get two waves travelling in opposite directions with the same frequency, speed and amplitude, then you get a STATIONARY WAVE. The peak doesn't move along. The peak in this case is in the middle of the string and it just goes up and down in that skipping rope pattern. Fixed points are called NODES and this oscillating maximum in the middle is called an ANTI-NODE.
