DrainSpin North and South of the Equator

November 26, 2006 8:33 PM

Do drain's really drain counterclockwise in the Southern hemisphere?

I heard this years ago and took it at face value as I had never traveled to south of the equator. Is this true?

posted by goalyeehah to science & nature (18 answers total)

no.
posted by drjimmy11 at 8:35 PM on November 26, 2006

See point #3
posted by forallmankind at 8:36 PM on November 26, 2006

See also The Straight Dope.
posted by Paragon at 8:53 PM on November 26, 2006

Also, notice that your drain does not always drain clockwise in the Northern hemisphere. That should save you a trip if you want to verify things.
posted by tkolar at 9:13 PM on November 26, 2006

Also debunked on Snopes. And please avoid the greengrocers' apostrophe.
posted by RogerB at 9:22 PM on November 26, 2006 [1 favorite]

News Flash!! In the Southern Hemisphere just moments ago in a series of haphazardly controlled experiments, water spiralled anti-clockwise down the drain (the myth suggests that it StraightDope).

BTW, contrary to what StraightDope claims - we don't have Hurricanes - we have Cyclones, which poses another question: What happens on the equator?
posted by strawberryviagra at 9:26 PM on November 26, 2006

that should read:
.... the myth suggests that it should spiral clockwise in the South, according to StraightDope ....
posted by strawberryviagra at 9:29 PM on November 26, 2006

Do drain's really drain counterclockwise in the Southern hemisphere?

In answer to your actual question, yes, they do occasionally, but not necessarily always.
posted by Pollomacho at 9:43 PM on November 26, 2006

Typically, hurricanes won't start until you're five degrees (about 310 miles) away from the equator.
posted by adipocere at 9:48 PM on November 26, 2006

In a nutshell, the Coriolis Effect is too weak to have an effect on the movement of water around a sinkhole.

Its effect is only apparent over large areas, such as a tropical storm or cyclones.
posted by TheOtherGuy at 9:52 PM on November 26, 2006

TheOtherGuy has it right. The forces that affect the way water spins in a sink are dominated by the design of that sink, not the Coriolis Effect.
posted by twirlypen at 11:15 PM on November 26, 2006

Do drain's really drain clockwise in the Northern hemisphere?
posted by brockerst at 2:00 AM on November 27, 2006

The moon is upside down down there, though. Freaky!
posted by 31d1 at 2:41 AM on November 27, 2006

My partner saw a demonstration at the equater where two soda bottles were turned over at the equator, each on opposite sides. The water swirled down in opposite directions on each side. I wonder how they made it do that.

Aside from the accepted idea that the coriolis is too weak to cause this, it seemed to me to be rediculous to suggest the effect could be observed at such trivial distances apart, at the equator.

My drain went down clockwise. I am in the southern hemisphere. I've been waiting for see this come up, because I can never remember which way it goes up north.
posted by Goofyy at 3:40 AM on November 27, 2006

I'm in the South as well Goofyy and the video I posted above shows it going anti-clockwise. The bowl is symmetrical.
posted by strawberryviagra at 3:48 AM on November 27, 2006

My partner saw a demonstration at the equater where two soda bottles were turned over at the equator, each on opposite sides. The water swirled down in opposite directions on each side. I wonder how they made it do that.

This demonstration appears in an episode of Michael Palin's Pole to Pole, too. It's a truck for the benefit of tourists.
posted by caek at 4:28 AM on November 27, 2006

well, quite a few years ago i tried an experiment in my northern hemisphere bathtub. I wasa easily able to reverse the direction--but found that often, after a minute or so, it would revert back to clockwise. I concluded that the effect was there, but easily manipulated by other factors.
posted by lester's sock puppet at 5:54 AM on November 27, 2006

Also note the Straight Dope article is the first hit in the obvious Google search.
posted by DevilsAdvocate at 10:58 AM on November 27, 2006