system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does the whole stream change it's course when you run water from the faucet and barely touch the side of the stream?
gpt
The viscosity (the way the water particles try to stick together) of the water means that when a few particles are diverted, they pull on the other particles around them and it turns into a chain reaction of movement. Imagine pinching a tubular curtain about halfway between and the floor and the ceiling and pulling it up. The bottom of the curtain would hang under your hand and the other side would move similarly, because it is all attached. A choppy analogy, but a visualisation none the less.

Also, it has a lot to do with the differing currents of the water stream pushing it all around.