First watch this
Now, do you think the water truly flowed backwards? Is it really possible for sound to become a pump strong enough to overcome gravity?
The sound could break the stream of water into droplets. The room will be using fluorescent lighting which is actually pulsing on and off at 50 or 60Hz. The camera is also filming at a certain number of frames per second. The combination creates the same effect as using a strobe light in a disco or to set the timing on an older car. The drops don’t go backward, you see one droplet, then the one slightly higher up was actually a different droplet.
No I don’t, but I can recognise footage being played backwards when I see it.
Can you really? Ever heard of stroboscopic effect?