Stationary Waves

So apparently:

1. For a stationary wave, all points between one node and teh next node are moving in phase. For a progressive wave, all points along a wavelength have different phases.

2. For a stationary wave, all points have different amplitudes. For a progressive wave, all points have the same amplitude.

The question is,
WHY?
How do we know this?

I don't get it.

Thanks.

Reply 1

teachercol

Have you ever set up a standing wave on a string and seen how the string moves?

Reply 2

vaporize

Thanks- I just looked at an online applet that showed a moving stationary wave, and it helped! I understand the amp thing now. I still don't get the phase difference.