Tell us something we don’t know.

[2LaneCruzer]

Really enjoyed the pneumonics. One other is Roy G. Biv, for the colors of the rainbow (or optical spectrum).

But I believe the Coriolis effect is too weak to dictate what direction a toilet or sink drain will swirl, it is likely dictated more by design or installed slope of the not perfectly circular appliance. Coriolis effect is real, but requires a much larger system to apply noticeable torque.

What he said.

 

[WinterDeere]

The design of the container holding the water doesn't have much effect. I've just filled and drained both kitchen sinks (different sizes and shapes) the Laundry sink and the Bathroom sink. All 4 sinks were filled and left until there was no water movement from the filling. the sinks were plastic or stainless steel.
In all instances the water rotated clockwise.

That is interesting, and something I cannot explain. Seems that with 4:1 odds, too coincidental to easily explain away, unless all four counters were installed by the same builder with the same imperfect level.

I have no horse in this race. While I'm an engineer who understands the physics involved, I haven't dedicated my career to becoming an expert on the Coriolis effect, and am just repeating the conclusions of those who have. Their conclusions have been overwhelmingly that the Coriolis effect does not have any impact on the direction water drains from a sink or toilet, as the system is too small and the low strength of this force when applied to such a small system is overwhelmed by other factors (installed slope, surface imperfections, jet design, drain shape, etc.).

But perhaps in the case of a still sink, with no injection of fresh water (toilet flush scenario), these other effects are neutralized to a point where Coriolis can actually do his work. One doesn't negate the other, the flushing toilets that started this debate are still a separate problem, but perhaps the still sink is an ideal-enough test bed to see this effect.

Any southern-hemisphere members here, who can repeat Shooz's experiment?

 

[Fuddyduddy1952]

When I pinch a loaf I could care less if it goes clockwise counterclockwise or straight as long as it goes down.

 

[MossRoad]

While standing in our bathroom this morning, I watched the sink drain clockwise and the toilet drain counter clockwise. I think the cat wondered what the %$^! I was staring at.

 

[LD1]

The design of the container holding the water doesn't have much effect. I've just filled and drained both kitchen sinks (different sizes and shapes) the Laundry sink and the Bathroom sink. All 4 sinks were filled and left until there was no water movement from the filling. the sinks were plastic or stainless steel.
In all instances the water rotated clockwise.

Repeat the same test.....but instead try and intentionally with you hand make the water swirl CCW and see how quickly it self corrects back to CW

 

[kevin37b]

Marks very extravagant mother's aunt just sent us ninety parakeets.
I remember that from 55+ years ago.
Mercury
Venus
Earth
Mars
Asteroid belt
Jupiter
Saturn
Uranus
Neptune
Pluto

You need help !

 

[MossRoad]

Repeat the same test.....but instead try and intentionally with you hand make the water swirl CCW and see how quickly it self corrects back to CW

Yep. It does. Still not the coriolis effect, but it does reverse direction.

 

[WinterDeere]

When I pinch a loaf I could care less if it goes clockwise counterclockwise or straight as long as it goes down.

If only Galileo had faced similar indifference.

I have 14 sinks, 4 toilets, three showers, and two jacuzzi tubs in this house. Perhaps I need to set aside some time this evening for testing and observation.

 

[LD1]

Yep. It does. Still not the coriolis effect, but it does reverse direction.

You can believe what you want. But millions of sinks in the northern hemisphere drain CCW and southern that spin CW. It cant be coincidence or a fluke design of EVERY sink made in the respective hemisphere

 

[MossRoad]

You can believe what you want. But millions of sinks in the northern hemisphere drain CCW and southern that spin CW. It cant be coincidence or a fluke design of EVERY sink made in the respective hemisphere

I think you're arguing your point backwards there...