During one of my first year projects at the Faculty of Aerospace Engeneering I mentioned the fact that a lot of people think that water flushes down the drain counterclockwise on the northern hemispheren and clockwise on the southern hemisphere. I was shocked to see that 6 out of 8 students (future scientists!) believed that as well. They even said they had learned it in high school. I think it's so weird that teachers know about a fenomena like the coriolis effect, but don't know that on such a scale it's negligible. Because in fact what they believe is that the difference in rotational speed of the Earth between two points that are maybe 2 feet apart causes the water to flow in a certain way. To me that's like saying that the temperature in the US will raise when I light a candle here in Holland [img]/phpBB/images/smiles/icon_smile.gif[/img].

You wonder if these people ever took a bath. I remember playing with the whirlpool, making it spin one way and then another, long before i heard of the coriolis force.

Some people think that the water in a toilet flushes the way it does because of coriolis. I guess they never looked at the water coming out of the jets under the rim. But then, i guess a number of people don't know the moon can be visible during the day time. Oblivious. What did Holmes say? "You see, but you do not observe"?

In my mind there is some question about all of this. a few years ago when we were discussing this on the old BABB, I did a little testing.

I started noting the direction of spin of the water draining from my bath tub. It always spun counter clockwise (CCW). Just for yuks, I tried stirring the water clockwise to force the issue. It didn't work. The water would slow and then spin CCW.

I even took it a step further, figuring that there was some aspect of the drain fixture that caused CCW spin. Borrowing some guages from a machinest neighbor, I measured the drain for plum (verticle trueness), concentricity (roundness) and the little supports for the stopper for some kind of bias. For something that is stamped out by the thousands, it was remarkably precise in all aspects, including the levelness of the tub flange.

I know it was a stupid waste of time but I just had to know. [img]/phpBB/images/smiles/icon_rolleyes.gif[/img] While it may not be corriolis effect, there is some aspect of my bath tub that causes the water to spin down the drain CCW every time.

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It's just one of those damn things of which there are many few. -- Dan Blocker

Russ, check your drain for it's location. Is it slightly closer to one side of the tub than the other? You'll also need to make sure the entire tub surface is level and symmetrical. If one corner at the far end of the tub is higher, that could affect the draining.

Also, check the faucet on its location. If the water is coming into the tub off-center, that could introduce a bias into the motion of the water molecules that, I suppose, could last until the plug is pulled . . . [img]/phpBB/images/smiles/icon_smile.gif[/img]

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SeanF

"Ask to understand, but don't challenge unless you have the knowledge."--NEOWatcher

The contents of this post are ©2008 by SeanF and may not be copied or retransmitted in any form without the express written consent of SeanF

Ahh, no fair. I was going to suggest the faucet. The faucet in our tub was noticeably off-center--it tilted so the water angled towards the hot tap. Apparently currents caused by filling the tub can take a long time to settle (hours to days).

There's a little bit about this in the BA's book. Dr. Plait also writes about the village on the equator where one of the locals demonstrates to busloads of tourists how a tub drains in different directions on either side of the equator. The BA explains how this little scam is run, but I'm not going to spoil it here!

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Microsoft is over if you want it.

The bar has been lowered for the promotion of ATM ideas; the bar for the acceptance of ATM ideas must remain high.

I was watching a cooking show where the cook was emptying a bottle of wine into a jar. He gave the bottle a swirl to set up a whirlpool to empty faster. It would have been a good place to put in a bogus N/S hemisphere reference, but he refrained.

Now what would happen if he was to take an electric mixer to the bath water? Would that alter the currents within the bathtub enough to counter act the currents caused by the bathtub being filled?

<font size=-1>[ This Message was edited by: Nightfall on 2003-03-05 15:49 ]</font>

Of course. But it won't exactly negate them, probably. So there'll be residual ones from something, anyway.

There's an episode of X-files where Mulder determines that there is witchcraft or some other oddness going on since the water in the drinking fountain was going down the drain the wrong way.

Of course, I'm screaming at the TV that the reason it's doing that is because there are metal baffles on the drain directing the water that way. None too observant, that Fox Mulder. [img]/phpBB/images/smiles/icon_smile.gif[/img]

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Jeff Schwarz
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Argh!! They booby-trapped their sun!!****--Invader ZIM

The simpsons did a whole episode on this one effect. [img]/phpBB/images/smiles/icon_smile.gif[/img]

A very funny episode.

That's not the only BA in X-files [img]/phpBB/images/smiles/icon_smile.gif[/img]

Seems like that might introduce some very unwanted current into the tub. [img]/phpBB/images/smiles/icon_biggrin.gif[/img]

Rich

True, but that one always stuck in my craw as being the most egregious.

I kept thinking that it would be a cool special effect to have the water going down the opposite way than the manuafacturer's intended; i.e. going uphill, over baffles, etc, just so it can go clockwise when one would expect it to follow the baffles and go counterclockwise. I'd give it to Mulder then. "Yessirree. There's something odd going on in this high school."

Instead, I was hoping for Crow T. Robot to say "Look Scully! There must be Black Magic (tm) going on here. The water in this water fountain is following basic engineering priciples!"

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Jeff Schwarz
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Argh!! They booby-trapped their sun!!****--Invader ZIM

Including, apparently, the authors of the Book of Genesis. [img]/phpBB/images/smiles/icon_wink.gif[/img]