It doesn't always turn clockwise (assuming you're in the Southern Hemisphere), that's just an old myth based on the effect of Coriolis force on large scale things such as air masses, but it plays no part on water in a sink or toilet, which are many, many times smaller than a cyclone.
clockwise
This is the Coriolis Effect, though it does not apply to processes as small as water draining in a sink, for example.
Yes, I almost always drink sink water and never get sick, although it may vary from place to place.
Not necessarily. Snopes does a good job of de-bunking this myth: http://www.snopes.com/science/coriolis.asp
No air or any form of gas will always rise to the surface (as a bubble)
No. Only solids denser than water will sink. The means a solid will only sink in water if it weighs more than an equal volume of water. Solids that float in water include ice, wood, and fat.
Maple syrup will sink but water is unable to sink because it is water.
the water sink is not solid and liquid
object that sink in water
Doesn't always, depends on amount of air inside, if it is less dense than water, it will float.
Because you will always have air in your body , if u let it all out you will sink
A jet-ski will only sink if it has been holed, or it's hull otherwise opened up to the water- even then, the damage has to be very serious, because their hulls are divided up into several water-tight compartments. But they certainly don't sink when they are stationary- they float under normal circumstances, just like boats do!