View Full Version : Have you ever thought . . .

Scott Rosen
03-12-2001, 01:31 PM
Just a few minutes ago, doing what I do best, I was watching the water drain from the bowl and I noticed that as it drained it flowed in a clockwise direction. It occurred to me that given the huge number of flushes every day, the clockwise flow of water was causing the needless waste of precious energy resources (at least here in the Northern Hemisphere).

Shouldn't toilets be designed to take advantage of the coriolus effect? If the flushes flowed counter-clockwise, there would be a small gain in efficiency, which I think would result in less water needed per flush and less force needed to propel the flush. Multiply that by four times a day per person, times 200 Million people in the USA alone, and WOW! We could save so much energy, we could forget about drilling in Alaska.

To the credit of those people associated with wooden boats, my old-fashioned bronze Wilcox toilet (designed before fiberglass boats were even a twinkle in some moron's imagination) flushes counter-clockwise. I guess if I ever travel South of the Equator, I'll have to flush it upside down.

[This message has been edited by Scott Rosen (edited 03-12-2001).]

03-12-2001, 01:50 PM
Don't know about everyone else but had to look up - Coriolis (note capital C).
....an apparent force that as a result of the earth's rotation deflects moving objects (as projectiles or air currents) to the right in the northern hemisphere and to the left in the southern hemisphere.

Don Z.
03-12-2001, 02:07 PM
Hey, I was just in the southern hemisphere last month, and I'll be back there next week... I'm sorry to tell you, but it doesn't seem to matter... Water goes where it will...

03-12-2001, 02:25 PM
How about small hydro-electric generators in the toilet bowl. I'm sure it would produce a very small amount of energy, but add'em all up... How about the same in the sink and tub drains. No sense in wasting gravitional force.
Plumbers would love this as it would give them tons of new work, and how about the maintenance of all these things. I can only imagine how these little turbines would clog up. This could be a whole new industry. I think I just figured out what that post was about awhile back. The one about the mysterious new invention that would change society forever. http://media5.hypernet.com/~dick/ubb/wink.gif

03-12-2001, 02:41 PM
winter is real bad this year hey???

03-12-2001, 02:53 PM
Scott, you may be right to be concerned about the efficency. I believe the friction forces due to tides flowing through the Bering Straits are actually slowing the earths revolution. Not much but we should prepare now for the Y2Billion bug.

Don Z. I don't think toilet bowls are the proper test for Coriolis Effect as the positioning of the flush holes overcome it. Check the sink.

Another interesting Coriolis effect which I have not personally verified (maybe one of the upside-downers can verify this) is that climbing plants that entwine their supports, grow in a right-hand helix in the northern hemisphere and left-handed (sinister) in the southern.

Ian McColgin
03-12-2001, 03:07 PM
I believe I've already related how the Coriolis Effect slowed Captain Cook's chronometer due to all that time at high southern latitudes attempting to double the Cape . . .

John B
03-12-2001, 03:11 PM
We do drive on the left,We also tend to vote a bit to the left, but as to the plants.... It's so hot at the moment, they just grow where ever , which ever way they like. I shall have to consult my resident amateur horticulturist as to which way the Bouganvillia spins.
I'm pretty sure that my multi purpose rotary gardening device ( lawnmower ) turns to the right but then again if you look at it from the grass's point of view........

Ross Faneuf
03-12-2001, 03:13 PM
I guess I'll violate the fun-loving spirit of Miscellania. The Coriolis effect is far too weak to account for the vortex direction in plumbing. It operates over large distances - like the one which causes the vortex direction of storms which move from the tropics towards the poles.

Some years back, a scientist set up an experiment to demonstrate that the Coriolis effect could determine vortex direction. He had to set up the experiment extremely carefully to demonstrate the effect - perfectly symmetric bowl, perfectly round, smooth drain, everything dead level, water allowed to sit for hours so there would be no trace of currents etc etc. After all that, the Coriolis effect could be demonstrated statistically.

All that said, it's also true that naval gunnery computers, at least, had to account for Coriolis effects at long ranges. You more experienced military types can comment as you please on other ballistic objects.

bob goeckel
03-12-2001, 03:13 PM
4 times a day? jeeeez Scott see a doctor will you. http://media5.hypernet.com/~dick/ubb/biggrin.gif

03-12-2001, 03:15 PM
I gotta tell ya, as long as the duty goes down the pipe and the tomatoes climb up the trellace, I couldn't care less.

Seriously, the Coriolis effect is so minimal in nearly any containable body of water and any attempt to harness that energy into a usable form will undoubtedly end in failure. That blasted law of thermodynamics comes into play every time and then we end up with less than we started with.

Oh well, giving credit where credit is due, it is dreaming like yours that advances our civilization.

Take Care.


Tom Beecroft
03-12-2001, 03:57 PM
I used to sell devices that used a vortex to separate solids from liquids. We were amazed at how many engineers with years of fluid dynamics education were so ignorant of how weak the coriolis effect is. Even the rotation of pumps many metres away from the drain is enough to change the rotation of the water.

It seems that everyone "knows" the water drains differently from northern to southern hemisphere, but few people bother to actually look, as Scott has.

For a good explanation, and an illustration of how to fake it, see http://www.ems.psu.edu/~fraser/Bad/BadCoriolis.html

Greg H
03-12-2001, 04:51 PM
I can verify that water does spin down the drain in a counterclockwise direction in the southern hemisphere. I did a test with several different drains last time I was there. Whether it is because of the Coriolis effect on the water or the engineers, I can't tell. http://media5.hypernet.com/~dick/ubb/smile.gif

03-12-2001, 05:19 PM
We performed a test when sailing across the equator. In the northern hemisphere the water spiralled away in the opposite direction of the southern hemisphere test.
And as we crossed the equator - the water went straight down! http://media5.hypernet.com/~dick/ubb/smile.gif

Ed Harrow
03-12-2001, 06:12 PM
Lots of experience above 0 degrees latitude, limited experience below, but I took the opportunity to investigate the potential. As to which way the water's going to swirl - I believe it's just a crap shoot.

03-12-2001, 07:55 PM
Back in the late '50's when I was a handsome young seasonal naturalist on the south rim of the grand canyon, leading nature walks, I had a favorite place to stop to talk about bark twining one way north of the equator and another south. I leaned against the juniper that twisted one way as I talked about the phnominum (where the heck is that spell checker?) using the tree 10' away as an example. As I moved away from the tree i was leaning on I observed, "So, the equator must run right throught here." Wasn't I cute? In those days maybe?

Counter clockwise junipers were rare (or was it clockwise) but they did occur. I suspect the twist was genetic.


Greg H
03-13-2001, 07:56 AM
21000 http://media5.hypernet.com/~dick/ubb/smile.gif

Scott Rosen
03-13-2001, 11:46 AM
I conducted a little scientific observation. I flushed a number of toilets, some of them flushed in the clockwise direction, the others counter-clockwise.

In all instances, the ones that flushed counter-clockwise used less water, finished the flush faster and emptied more of the solid matter. These flushes were in the same direction as the Coriolis force.

The clockwise flushers were noticably slower to start, slower to finish and left more solid material in the bowl after the flush. They also required more water to perform the flush. The most unusual characteristic of these clockwise flushers was the slight delay from the time I pulled the plunger to the time the water started swirling. It was as if the force of the water jets had to overcome the Coriolis force of the water in the bowl in the opposite direction, which made it look as if the standing water was inert and had greater mass than the water coming from the jets.

You can deny it if you want. But as slight as the Coriolis force is, it is nonetheless a noticable factor in flushes. I guess it's most noticeable in large storms, which rotate counter-clockwise in the Northern Hemisphere and clockwise in the South.

Which brings me to another question. Why is the Sou'wester hat not called a Nor'easter? Where I live, when the weather is out of the Southwest, you usually have dry, sunny conditions. When it's from the N.E., it's usually wet and foul.

Some many imponderables, so little time.

J. Dillon
03-13-2001, 01:19 PM
See....sh ! Scott, is that all you got to do, watch s##t go down the bowl ?

Better start cutting wood for that Haven. http://media5.hypernet.com/~dick/ubb/wink.gif

Scott Rosen
03-13-2001, 01:37 PM
J.D., I appreciate your thoughts.

Unfortunately, I am forced to spend a small amount of time each day watching the water go down, and I haven't figured out a way to cut wood while using the bowl. http://media5.hypernet.com/~dick/ubb/wink.gif Since I've already finished the latest issue of WB, I need to do something to occupy my mind . . .

Ross Miller
03-13-2001, 02:37 PM
This reminds me of the time I heard a mother describe how her two-year-old son, at the apex of some Freudian stage, stood by the bowl sadly waving goodbye to his latest creation.

bob goeckel
03-14-2001, 11:12 PM
Scott, i must clarify my doctor statement: it ain't no regular(pardon the pun)doctor you need. can you say "bulking agent" boys and girls!

George Roberts
03-14-2001, 11:32 PM
I think artillery shells exhibit conservation of angular momentum. They move too fast for Coriolis to be important.

There are all sorts of wonderful properties of rotating fluids. One being they support wooden objects.

03-15-2001, 06:02 AM
a friend of mine was really into vortices a few years ago, as they relate mystically to organinc agriculture, if you can believe it. one of the books he was reading, which seemed more scholoarly than most, stated that water has an incredible "memory" so, in the case of bathtubs and sinks, whichever way you swished the water, which got it flowing in a certain, that's the direction in which it will go down the drain. the water keeps moving in that direction for a long time and it doesn't take much movement to put it into motion. as far as toilet bowls go, i've been told it has more to do with the shape of the bowl than the coriolis effect.

Scott Rosen
03-15-2001, 08:35 AM
I think I need to clear something up. Usually, in any given day, a make a number of trips to the head. But only one of those relates to solid waste. The other trips are of the purely liquid variety. I may need a head shrinker to help me get over my apparent infantile obsession with bodily functions, but my discharge lines are running just fine.

03-15-2001, 09:28 AM

You sly dog. Perhaps I'm missing sumpthin' here, but I'm beginning believe you are a part (perhaps a master mind) of the anti-Christ, Jewish world domination conspiricy, designed to slow the Earths rotation, and eventually its revolution, and eventually we'll all be held... why, held hostage to the yet undiscovered asteroid, code named Yaweh, controlled by space aliens (Nephilim, huh, huh, explain that one) you are in league with.

How do you plead? I think you better answer to these charges before you paint your bottom, or countermand the Coriolis affect, or what ever it is you're up to. Oh my, land a goshen, sakes alive. He he.

I almost said, "we're watching you," but then it suddenly didn't feel quite so funny.

Peace brothers, Jack

Jonathan Kabak
03-15-2001, 10:00 AM
To Address Scott's question of the Sou'Wester:

The only thing my little brain can figure is that the nice big trailing edge that keeps all the nasty weather from flooding down your collar faces Sou'West in a Nor'Easter.

Comments anyone?


Ross Faneuf
03-15-2001, 10:17 AM
Maybe SouWester is a Brit/English term? Anyone over the pond know?

03-15-2001, 04:36 PM
jonathan's got the answer, according to my sources along the maine coast. in a northeaster, you'd want to be facing southwest, and that long trailing edge does, indeed, cover your collar (or downspout) when you face southwest.

Phil Young
03-15-2001, 11:23 PM
You guys have got duo flush toilets up there haven't ya?

02-27-2004, 01:22 AM
For an explanation of the physics involved:

Which Way Will my Bathtub Drain? (http://math.ucr.edu/home/baez/physics/General/bathtub.html)

02-27-2004, 09:29 AM
... well, with the 'high-efficiency' 1.6 gallons-per-flush that are now put in new homes, it often takes TWO flushes ...

Well, I guess, overall the efficiency is increased! ;)

Nicholas Carey
02-27-2004, 04:15 PM
The coriolis force is so weak in small bodies of water like sinks, toilet bowls, bathtubs, etc., that it is outweighed by the myriad other forces at play: friction, assymetry in the drain or the basin, current/turbulance left over from filling the basin (which may take a week or more to die down), etc.

Physics nerds being…well…physics nerds, people have looked into this.

David J. Van Domelen of the OSU Physics Department writes in "Getting Around The Coriolis Force" (http://www.physics.ohio-state.edu/~dvandom/Edu/newcor.html):
"Fine," you may say, "that explains storms. But what about water going down the sink?" In fact, this question is a good "hook" for getting students interested in the Coriolis force in the first place.

Because the Earth's angular velocity is so small (360 degrees per day, or about 7 x 10<span style="vertical-align:super;font-size:smaller;">-5 radians per second), the Coriolis force isn't really significant over small distances.And Cecil Adams of the Chicago Reader (http://www.chireader.com/)'s syndicated column The Straight Dope (http://www.straightdope.com/) &mdash; "Fighting ignorance since 1973&mdash;it's taking longer than we thought!" &mdash; has answered this very question in his immortal "Do bathtubs drain counterclockwise in the Northern Hemisphere?" (http://www.straightdope.com/classics/a1_161).
Well, there is such a thing as the Coriolis effect. It explains why macroevents such as hurricanes rotate in a clockwise direction in the Southern Hemisphere and counterclockwise in the Northern Hemisphere. However, when you get down to itty-bitty phenomena such as the water draining out of your bathtub, the Coriolis effect is insignificant, amounting to roughly three ten-millionths of the force of gravity (in Boston, at least, which is where they happened to do the measuring).

The boring truth is that water drains every which way no matter what hemisphere you're in, for reasons which have to do mostly with the shape of the drain, the way you poured in the water in the first place, and so on.More at:


ken mcclure
02-28-2004, 07:13 AM
Which way do the dogs turn downunder before laying down. Up here, they turn clockwise.