The Coriolis Effect

[Atomic]

Put up your hand if you think water in the Southern Hemisphere drains in a different direction to the Northern Hemisphere. I, for one, was sure that it did.

I was so sure in fact that I made quite a substantial wager with an American friend who said that it didn't matter which hemishpere you were in, water can drain anyway it wants down the plug hole - it's dependant on the bowl and drainage hole.

As it turns out, I think he's correct; much to my (and my wallet's) horror. On the slim chance that he's wrong, can anyone prove to me that the Coriolis Effect influences the direction of water drainage?

 

[dibo]

It's a real effect but it's not stronger than say, you swishing the water in the other direction to reverse the force of the vortex.

 

[Atomic]

yes, that's what I've realised. It effects weather systems and is far too weak to act on water in the sink. Lisa Simpson has a lot to answer for!

 

[Marquee]

Well you both are correct. As dibo says, the Coriolis effect in a sink/bath is very weak. The factors of the basin shape and whether the water still has velocity from where it came from (i.e. the tap) will usually overcome this. If you where able to minimise all the external factors, then the direction would depend on the Coriolis effect in each hemisphere.

 

[dibo]

A wide, smooth cylindrical vessel where water flows out sufficiently quickly from a central hole will show the Coriolis effect if undisturbed. It's certainly real. Even in a sink or bathtub, left undisturbed the vortex will move the way the Coriolis effect predicts.

But in a toilet, for a start the flow of water is turbulent, and for seconds the water is shot out at speed. The Coriolis effect will *influence* the water flow, but not necessarily in such a way as to be clearly distinguishable - the pattern of turbulence might be different, but who's going to notice?

All this said the fact that you *can* defeat the Coriolis effect using external forces 'proves' it doesn't exist in the same way that jumping in the air 'proves' gravity doesn't exist.

For a final winner, check the circulation of cyclonic storms - they differ hemisphere to hemisphere. The reason is the Coriolis effect.

 

[FFC Mariner]

Will someone be posting details of the speed at which paint dries soon?

 

[hasbeen]

I personally don't care in which direction the water flows when I flush the toilet. As long as there is no wee smiling thing (jobbie) left after it.

 

[serious14]

Operator: This is the international operator.  Will you accept a collect call from....

Bart: [lowering voice] Uh, yes.  Uh, ahem, this is Dr. Bart Simpson of the International Drainage Commission.  It's an emergency.

Tobias: If it's an emergency, then.
   
Bart: We understand some drains in your area have been malfunctioning, sucking in people and whatnot.
 
Tobias: Willikers!  That's awful.

Bart: [gravely] Indeed.  We need you to check your sinks and toilets and tell us which way the water is going, and please!  Stand clear.
         
[Tobias checks sink and toilet]  Tobias: [breathless] The fixtures...they're all draining clockwise sir!
   
Bart: D'oh, she was right, stupid Lisa science queen - look, why don't you just check your neighbor's drains?  I'll hold.
         
[Tobias rides trike off down long dirt road]
Milhouse: [at the window] Hey, Bart!  The bakery caught fire and all of downtown smells like cookies!  Wanna go smell?
   
Bart: Yes...yes, I do.  [leaves phone off hook]
         
[later that night, Bart walks back into the kitchen]["Hello!  Sir!  Sir!" is heard from phone, still off thehook]
   
Bart: [picking up phone] Huh?
 
Tobias: I've returned from the Koolamuggerys' place...they're draining clockwise too!
   
Bart: Draining?  I don't care about that any more.

Tobias: Are we in any dang -- [Bart hangs up]

 

[adz]

the scary thing is you wrote all that from memory

 

[Jazzie]

Will someone be posting details of the speed at which paint dries soon?

That's easy ... just look on the label on the back of the tin!  8)

 

[Jazzie]

Well you both are correct. As dibo says, the Coriolis effect in a sink/bath is very weak. The factors of the basin shape and whether the water still has velocity from where it came from (i.e. the tap) will usually overcome this. If you where able to minimise all the external factors, then the direction would depend on the Coriolis effect in each hemisphere.

What if you lived on the equator?