# Hemisphere question **URL:** \ **Category:** Factual Questions\ **Created:** [March 14, 2004, 9:51pm UTC](https://boards.straightdope.com/t/hemisphere-question/234295 "2004-03-14T21:51:20Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![slumtrimpet](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@slumtrimpet](https://boards.straightdope.com/u/slumtrimpet)\ **Post date:** [March 14, 2004, 9:51pm UTC](https://boards.straightdope.com/t/hemisphere-question/234295/1 "2004-03-14T21:51:20Z")
We’re about to travel from the northern hemisphere to the southern one. I’ve heard, or course, that water swirls down the drain counter clockwise in the north and clockwise in the southern half of the world. First…is this really true? And second, does it change from one to the other exactly on the equator? In other words. If I lock myself into the loo on the plane and continually refill the sink, will I be able to tell when we cross the equator? ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [March 14, 2004, 9:53pm UTC](https://boards.straightdope.com/t/hemisphere-question/234295/2 "2004-03-14T21:53:38Z")
Nope, not true. The [Coriolis Effect](http://en.wikipedia.org/wiki/Coriolis_effect) is real enough, but not nearly strong enough to affect water going down a drain. In short, it will go down whichever way it wants to. ---
**Author:** ![Lobsang](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lobsang/32/4067_2.png) [@Lobsang](https://boards.straightdope.com/u/Lobsang)\ **Post date:** [March 14, 2004, 9:53pm UTC](https://boards.straightdope.com/t/hemisphere-question/234295/3 "2004-03-14T21:53:39Z")
> [@slumtrimpet](#): > > We’re about to travel from the northern hemisphere to the southern one. I’ve heard, or course, that water swirls down the drain counter clockwise in the north and clockwise in the southern half of the world. First…is this really true? And second, does it change from one to the other exactly on the equator? In other words. If I lock myself into the loo on the plane and continually refill the sink, will I be able to tell when we cross the equator? What’s the phone number for Australia? I’ll ask them. ---
**Author:** ![slumtrimpet](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@slumtrimpet](https://boards.straightdope.com/u/slumtrimpet)\ **Post date:** [March 14, 2004, 9:58pm UTC](https://boards.straightdope.com/t/hemisphere-question/234295/4 "2004-03-14T21:58:38Z")
Thanks guys. Now I’m bummed. ☹ I’m going to have to rely on the stupid plane tracking video to tell when I’ve crossed the equator. **Lobsang** , It’s country code 61 … maybe they have a number for information 🙂 ---
**Author:** ![j666](https://avatars.discourse-cdn.com/v4/letter/j/9de0a6/32.png) [@j666](https://boards.straightdope.com/u/j666)\ **Post date:** [March 14, 2004, 10:12pm UTC](https://boards.straightdope.com/t/hemisphere-question/234295/5 "2004-03-14T22:12:10Z")
Oddly enough, you are not this first to ask. [http://www.straightdope.com/classics/a1\_161.html](http://www.straightdope.com/classics/a1_161.html) ---
**Author:** ![gluteus\_maximus](https://avatars.discourse-cdn.com/v4/letter/g/f17d59/32.png) [@gluteus\_maximus](https://boards.straightdope.com/u/gluteus_maximus)\ **Post date:** [March 14, 2004, 10:27pm UTC](https://boards.straightdope.com/t/hemisphere-question/234295/6 "2004-03-14T22:27:52Z")
Can’t you just look out the window and watch for that red line? ---
**Author:** ![slumtrimpet](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@slumtrimpet](https://boards.straightdope.com/u/slumtrimpet)\ **Post date:** [March 14, 2004, 10:34pm UTC](https://boards.straightdope.com/t/hemisphere-question/234295/7 "2004-03-14T22:34:03Z")
ooh…good idea! I hope there no cloud cover. 😃 ---
**Author:** ![FatBaldGuy](https://avatars.discourse-cdn.com/v4/letter/f/ecd19e/32.png) [@FatBaldGuy](https://boards.straightdope.com/u/FatBaldGuy)\ **Post date:** [March 14, 2004, 10:41pm UTC](https://boards.straightdope.com/t/hemisphere-question/234295/8 "2004-03-14T22:41:50Z")
[Snopes](http://www.snopes.com/science/coriolis.htm) also has something to say on this subject. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [March 14, 2004, 11:21pm UTC](https://boards.straightdope.com/t/hemisphere-question/234295/9 "2004-03-14T23:21:06Z")
Of course, it doesn’t stop a guy at the equator in Kenya doing demonstrations for folks, using a basin of water and a twig. I believe he just gives the water a slight swirl while they’re not looking 😉 ---
**Author:** ![gluteus\_maximus](https://avatars.discourse-cdn.com/v4/letter/g/f17d59/32.png) [@gluteus\_maximus](https://boards.straightdope.com/u/gluteus_maximus)\ **Post date:** [March 14, 2004, 11:31pm UTC](https://boards.straightdope.com/t/hemisphere-question/234295/10 "2004-03-14T23:31:17Z")
> [@slumtrimpet](#): > > ooh…good idea! I hope there no cloud cover. 😃 😃 I hope it’s not a night flight! ---
**Author:** ![z1221z](https://avatars.discourse-cdn.com/v4/letter/z/ee7513/32.png) [@z1221z](https://boards.straightdope.com/u/z1221z)\ **Post date:** [March 15, 2004, 12:45am UTC](https://boards.straightdope.com/t/hemisphere-question/234295/11 "2004-03-15T00:45:08Z")
> [@Fat Bald Guy](#): > > [Snopes](http://www.snopes.com/science/coriolis.htm) also has something to say on this subject. Yes they are right; the coriolis force is much to small to have an effect on the vortex in your drain. But the snopes explanation is very simplistic, and it suggests only objects moving north or south will be affected by the coriolis force, but that´s not true. A cannonball fired due east or west will also be deflected, just like _any_ moving object will be deflected (to the left or to the right, dependig on the hemisphere). And that´s the hard part to understand. ---
**Author:** ![antechinus](https://avatars.discourse-cdn.com/v4/letter/a/fbc32d/32.png) [@antechinus](https://boards.straightdope.com/u/antechinus)\ **Post date:** [March 15, 2004, 2:17am UTC](https://boards.straightdope.com/t/hemisphere-question/234295/12 "2004-03-15T02:17:49Z")
> [@r\_k](#): > > Of course, it doesn’t stop a guy at the equator in Kenya doing demonstrations for folks, using a basin of water and a twig. I believe he just gives the water a slight swirl while they’re not looking 😉 Is he the chap who scammed Michael Palin? Apparently he turns to the right, to show onlookers, and get the water moving clockwise then steps over the equator and turns to the left (to show the same onlookers) to start the water moving anticlockwise. ---
**Author:** ![Askance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/askance/32/8281_2.png) [@Askance](https://boards.straightdope.com/u/Askance)\ **Post date:** [March 15, 2004, 2:21am UTC](https://boards.straightdope.com/t/hemisphere-question/234295/13 "2004-03-15T02:21:27Z")
> [@slumtrimpet](#): > > We’re about to travel from the northern hemisphere to the southern one. I’ve heard, or course, that water swirls down the drain counter clockwise in the north and clockwise in the southern half of the world. First…is this really true? How would you know if it did? Have you done some sort of comprehensive survey of drains where you live to determine that they all go in the same direction for a start? ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [March 15, 2004, 2:44am UTC](https://boards.straightdope.com/t/hemisphere-question/234295/14 "2004-03-15T02:44:35Z")
No that’s not right. If you go by sea you might get to be iniated by Davy Jones himself as a shell back. Goinmg by air worn’t cut it unless there is a new airborn ceremony. Tough Luck! ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [March 15, 2004, 5:26am UTC](https://boards.straightdope.com/t/hemisphere-question/234295/15 "2004-03-15T05:26:47Z")
> [@slumtrimpet](#): > > …will I be able to tell when we cross the equator? Bring a handheld GPS with you. Assuming the airline will allow you to have it on in flight, it will tell you exactly when you cross it. ---
**Author:** ![coop](https://avatars.discourse-cdn.com/v4/letter/c/87869e/32.png) [@coop](https://boards.straightdope.com/u/coop)\ **Post date:** [March 15, 2004, 5:44am UTC](https://boards.straightdope.com/t/hemisphere-question/234295/16 "2004-03-15T05:44:23Z")
I lived in Butterworth, Malaysia from December, 1977 to December, 1979. Water drained anti-clockwise all the time I was there. I am now living in a suburb near Sydney, NSW, Australia. 🙂 The water drains clockwise in my sink. Is that enough of an experiment 😕 ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [March 15, 2004, 6:10am UTC](https://boards.straightdope.com/t/hemisphere-question/234295/17 "2004-03-15T06:10:54Z")
> [@Q.E.D.](#): > > Bring a handheld GPS with you. Assuming the airline will allow you to have it on in flight, it will tell you exactly when you cross it. You cannot use them during flight. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [March 15, 2004, 6:14am UTC](https://boards.straightdope.com/t/hemisphere-question/234295/18 "2004-03-15T06:14:56Z")
> [@Duckster](#): > > You cannot use them during flight. That’s not necessarily true. It’s up to the airlines and the individual pilots. [Cite](http://gpsinformation.net/airgps/gpsrfi.htm). Some will, some won’t. Ask. ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [March 15, 2004, 6:30am UTC](https://boards.straightdope.com/t/hemisphere-question/234295/19 "2004-03-15T06:30:04Z")
> [@Q.E.D.](#): > > That’s not necessarily true. It’s up to the airlines and the individual pilots. [Cite](http://gpsinformation.net/airgps/gpsrfi.htm). Some will, some won’t. Ask. I sit corrected. However, I have yet to fly commercial aircraft in the US where the pilot said it was OK. In fact, the last few flights I took (the last being two weeks ago) they said GPS could not be used. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [March 15, 2004, 6:34am UTC](https://boards.straightdope.com/t/hemisphere-question/234295/20 "2004-03-15T06:34:45Z")
> [@Duckster](#): > > I sit corrected. However, I have yet to fly commercial aircraft in the US where the pilot said it was OK. In fact, the last few flights I took (the last being two weeks ago) they said GPS could not be used. I imagine permission is less common since 9-11-01. _shrug_ Or maybe you should smile when you ask 😉 [Next page](https://boards.straightdope.com/t/hemisphere-question/234295.md?page=2)