What Way Does Your Bathtub Drain?

[Tanalia]

I thought all water molecules existed in their ionic state...
.

Not all, but some. Water molecules may dissociate into separate ions (hydrogen [H+] and hydroxyl [OH-]), but, since they are oppositely charged, they tend to recombine fairly rapidly.

The effect by a magnetic field is deflection in different directions for the opposite ions you talk about in the OP--since the charge below even the macro level is essentially neutral, the effect should be minimal or even non-existent, shouldn't it?

If you say so, but the hydroxyl ions are 33 times as massive as the hydrogen ions. Would that make a difference?

Only 17 times as massive, but no. The force experienced due to the magnetic field is proportional to the charge, so it would be equal (though in opposite directions). This force would indeed accelerate the hydrogen ions faster than the hydroxyl, but the resulting momentum of each would be the same.


Details for any other lurking geeks :

pH is a measure of average hydrogen ion concentration of a solution. Pure water is pH 7, meaning 1.0e-7 mole of [H+] per liter, so a rather small fraction of the water is ionized at any moment.
Acids have a higher concentration of hydrogen ions, directly provided by the acidic substance (stomach acid contains hydrogen chloride, HCl, in solution called hydrochloric acid, directly providing more [H+] -- stomach acid is often around pH 2, or 1.0e-2 M/l, a significantly higher concentration that pure water, though still a small fraction of the total solution).
Alkaline solutions, on the other hand, provide more [OH-] which tend to bind with the free [H+] from the water, so fewer are available at any given time. The lower concentration is represented by a higher pH value (just as the higher concentration for the acid is a lower value).
Most people learn that the pH scale runs from 0 (very acid) to 14 (very alkaline), an this is true for most substances people will encounter, but it is quite possible to exceed these limits -- an extremely strong acid could have a negatove pH.

An acid would not be affected any differently by the magnetic field than water; although it has more [H+] than the water, the excess is balanced by the other component of the acid, [Cl-] in the case of hydrochloric acid.

[boppa]

interesting
i got 2 bathtubs,4 hand sinks,2 kitchen sinks and 2 laundry tubs

even just in my house i got an equal split-even to the tub types

ie 1 bath goes one way,one goes the other..
2 hand sinks go one way,2 the other..

and im `pretty sure' im not on the equator too

methinks local geometry of the sink/tub/etc is the deciding factor



(but its cool that im mr average in person tho..)
;-)

[HenrikOlsen]

The poll lacks a couple of possibilities, one of which (the one in my bathtub), is that it depends on how I got out of it.

[NASA Fan]

I know that it has been 9 months since the last post, but I thought that I would share my observation.

I filled my bathtub with about 6 inches of water, and turned the plug (I can't pull it out), and I could not see any direction to the water flowing out...even when I stirred the water clockwise, or counter clockwise.

So my vote would have to be straight down.

[hhEb09'1]

So my vote would have to be straight down.

We're going to have to throw out your datapoint as an outliar

[Argos]

What about your bathtub? Sinks are smaller, so the effect might not be the same.

Ok, I did it to my pool, just to find out that it drains... Right downwards (because it is forced by a pump). You owe me 50,000 litres of water.

[NASA Fan]

Who Me? I did not say that it was not possible for it to go straight down.

I'll tell you what, I will send you a bottle of water, then you only have to get 49,999.5 more liters of water. If you ask nicely, maybe one or two other poster will be kind and send a bottle.

[Argos]

It wasn´t directed to you, but since you´ve asked, I prefer Evian, please...

[jimbo]

always i have noticed the water going anti clockwise.until the other morning when it went clockwise.the only reason i can think that it went that way is that the drains were partialy blocked.or perhaps it was my hangover making the room spin.

[clop]

You're going to have to normalise the data because more people living in the northern hemisphere than in the southern hemisphere have responded.

I think (not being very good at statistics) that this means you have to divide the number of northern hemisphere votes in each category by the total number of northern hemisphere votes and divide the number of southern hemisphere votes in each category by the total number of southern hemisphere votes. Only then will you see if there is a relationship or not.

I'm in the southern hemisphere but rarely take a bath (we're very conscious of using water here in the driest state of the driest continent) so I'm sorry that I can't vote in your poll.

clop

[grant hutchison]

I do understand that there are folks living in countries on the equator who will "demonstrate" this effect for tourists. They take a big basin filled with water, walk across the equator to the north side, pull out the stopper, and the water circles one way. Then they refill the basin, walk to the south side of the equator, and the water circles the other way, amazingly enough. Of course, what you didn't notice, since you only saw them do this once or twice, was that after crossing the equator they always carefully turn around to face you again in the correct direction to start the water rotating the way they'd like imperceptibly.

The Kenyan demonstration of this which featured on Michael Palin's Pole to Pole TV series was particularly good, since the demonstrator got the expected directions of drainage wrong in his preamble, but in his subsequent demonstration the directions of rotation turned out to be just as he had (wrongly) predicted.
A very nice demonstration that other forces must predominate over Coriolis, and that they appear to be under the control of the demonstrator.

But there's a static demonstration set up beside an equator monument in Uganda, which doesn't allow for the "turn the bucket" trick to be used.
But the containers used are wide, flat dishes, and each of them has a spiral painted on its inside surface in thick white paint, indicating the predicted direction of rotation. Presumably this influences radial flow enough to set up the appropriate drainage spiral.

Grant Hutchison

[jimbo]

how about this ,when the room spins when you have had too much to drink is the direction affected by which hemisphere you are on?

[greatgreekcollector]

My bathtub drains straight down.

[Occam]

I think the most significant result of this poll, is that there are apparently more people with bathtubs in the Northern hemisphere, than the Southern.

[chrissy]

Mine goes counter clock wise even my kitchen sink.