I only just came across this. It's interesting how this myth has been perpetuated. The direction of rotation of water down a drain depends on a number of things, initial movement of that water, the shape of the container that's being drained, and so on. It can go either direction.
Now this will take me a little bit to decipher!
In physics, the Coriolis effect is an apparent deflection of moving objects when they are viewed from a rotating reference frame. In a reference frame with clockwise rotation, the deflection is to the left of the motion of the object; in one with anti-clockwise rotation, the deflection is to the right. The mathematical expression for the Coriolis force appeared in an 1835 paper by a French scientist Gaspard-Gustave Coriolis in connection with the theory of water wheels, and also in the tidal equations of Pierre-Simon Laplace in 1778. Early in the 20th century, the term Coriolis force began to be used in connection with meteorology.
The Coriolis effect is caused by the rotation of the earth and the inertia of the mass experiencing the effect. Newton's laws of motion govern the motion of an object in a (non accelerating) inertial frame of reference. When Newton's laws are transformed to a rotating frame of reference, the Coriolis and centrifugal forces appear. Both forces are proportional to the mass of the object. The Coriolis force is proportional to the rotation rate and the centrifugal force is proportional to its square. The Coriolis force acts in a direction perpendicular to the rotation axis and to the velocity of the body in the rotating frame and is proportional to the object's speed in the rotating frame. The centrifugal force acts outwards in the radial direction and is proportional to the distance of the body from the axis of the rotating frame. These additional forces are termed either inertial forces, fictitious forces or pseudo forces. They allow the application of simple newtonian laws to a rotating system. They are correction factors that do not exist in a true non accelerating "inertial" system.
Connie, it's certainly not the sort of thing to try to read when your mind is in 'slow mode', LOL. The impression I get (in simple terms, the only way I can grasp it) is that the Coriolis effect requiring the rotation of the planet needs the time of that rotation to start to have an effect. But being such a weak force, the situation in a bathtub, for example, doesn't allow enough time to begin to affect the water signifcantly. But existing motion in the water initially dictates the direction of rotation, then gravitational forces accelerate it, and Coriolis is no longer able to influence it. I hope that's clear, I'll have to read back over it again (a few times). I know what I mean, just hoping that's what I said
Sorry to hear about the colds! I hope you are OK now. I'm OK, going to have another grandchild from my DD. She just got married last month. They might leave for work to another town by the end of the month. Otherwise we're fine, enjoying Nicholas growing and talking a LOT! Waiting for spring to start gardening. Still crazy weather, warm for a few days, then freezing again. Raining right now and getting cold again.
Many congratuIations! I so know about talking alot as my two never stop
The weather has been pretty daft here too, 28c one day and 10c the next, what's going on?
I guess that's spring for you :confused:
Talking about talking, both my boys speak both Japanese and English and often mix the two
I'm Iooking forward to gardening though I've not touched itt in two years as a resuIt of contaminatiom from the Fukushma meItdown. We stiII have ceasium in the first few centimers of top soiI but what the heII I need to garden, It's what I do! I won't grow vegies onIy fIowers and frankIy at 65 do I reaIy nead to worry about stuff that may or maynot afect me in 20 years?
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