The whirlpool

What you can do here
Slowly turn the crank to get the rotor going. Gradually increase the rotation speed. Watch to see what happens to the liquid.


How it works
A spinning rotor puts the liquid particles around it in motion. They, in turn, move the neighbouring particles and the liquid responds to the spinning movement of the rotor. The liquid produces a whirlpool. When you look at a ball inside, you can find out what happens to an object near the whirlpool.
Even movement of the liquid at a speed which gradually decreases towards the walls of the vessel are called laminar flow while chaotic movement of the liquid which occurs after you stop spinning the crank is an example of turbulent flow.


Interesting facts
Whirlpools may form behind object washed by water. There are known instances of drowning as a result of being sucked in by a whirlpool near breakwaters at a seashore. When a whirlpool sucks you in, the best way to survive would be to dive and then to resurface next to the whirlpool.