Waves can constructively or destructively interfere when they meet.?

Question

What would happen in a football stadium if two "waves" collided? what is different about a "human" wave?

Answer 1

In technical terms, human waves don't obey "linearity".  If you have two waves in water, or on a string, and they meet so as to interfere constructively, you get a wave twice as high.  But people don't behave like that.  If two human waves are coming at you, one from each side, are you going to stand up twice as high?  Of course not.

That's one difference, another is that human waves are based on perception and human brains, which aren't exactly designed to do perfect wave propagation.  When two human waves meet, they should pass through one another, but that means that the people who just stood up and sat down for the wave on their right have to react also to the wave on their left.  With training I'm sure it could be done, but most likely, especially with the average half-drunk, stadium fan, they would get confused and the waves would die out when they met.