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Another important scientific poser

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  • Another important scientific poser

    Whirlpools, such as those associated with water going down a drain, rotate clockwise in the northern hemisphere. They rotate counterclockwise in the southern hemisphere. What do they do at the equator? Fall straight down?

    I crossed the equator several times when I was in the Navy, but I was too busy being abused or watching other people being abused that the thought of checking never crossed my mind. Anybody know?

    Prof

  • #2
    Originally posted by Prof View Post
    Whirlpools, such as those associated with water going down a drain, rotate clockwise in the northern hemisphere. They rotate counterclockwise in the southern hemisphere. What do they do at the equator? Fall straight down?

    I crossed the equator several times when I was in the Navy, but I was too busy being abused or watching other people being abused that the thought of checking never crossed my mind. Anybody know?

    Prof
    Interesting question. Id guess that they couldnt form on the equator cause of opposing forces.

    What happens to a cyclone as it passes over the equator? Does it change direction and become a hurricane?

    Comment


    • #3
      found this


      The Coriolis force is what causes hurricanes to happen. The force disappears near the equator and is ineffective between about 8 degrees North and 8 degrees South. Hurricanes can not function without the Coriolis force. This is also why early sailors would not like to get stuck at the equator. This area is called the Doldrums and have no winds.
      I would imagine its the same with Wirlpools

      Comment


      • #4
        http://www.thenakedscientists.com/fo...prev_next=next

        :D

        Comment


        • #5
          Well. It's reassuring to know that there are others who have as much time on their hands as I. Not sure that the aggregate of those posts contained in your link answered my question, though. I personally would like to think that it just falls straight through. That would look the weirdest, a characteristic highly desireable in any explanation of anything. Of course, Zara's reply is the most intriguing. That would explain why drains don't work near the equator.

          Prof

          Comment


          • #6
            ^^^ Prof, depends on the drain. ;)

            Actually, you can make it go either way above or below the equator depending on the shape of the sink and drain. Coriolis forces are irrelevant to sink drains.

            But the coriolis forces are opposite, so storm rotations reverse. :)
            "We will go through our federal budget – page by page, line by line – eliminating those programs we don’t need, and insisting that those we do operate in a sensible cost-effective way." -President Barack Obama 11/25/2008

            Comment


            • #7
              Originally posted by zara View Post
              What happens to a cyclone as it passes over the equator? Does it change direction and become a hurricane?
              There are no hurricanes at the equator. The hurricane belt is about 10-30 degrees north or south latitude.

              Occasionally there is formation closer, but they are always moving away from the equator, never toward it.
              "We will go through our federal budget – page by page, line by line – eliminating those programs we don’t need, and insisting that those we do operate in a sensible cost-effective way." -President Barack Obama 11/25/2008

              Comment


              • #8
                There seems to me that there is little agreement about this. Checked around the Web. Found a guy who agrees with you. Found a guy who thinks the flow directions are opposite but that in the Northern hemisphere it's counterclockwise. In my drain it's clockwise; Bammy is south, but not that south. Some people think that the coriolis affect doesn't have anything whatever to do with small systems, some say that it does. I suspect that it does, just not very much. I have faith that there is a right answer.

                I like this one:

                "If the spin did seem the opposite or appear so. I believe the coriolis force could affect small systems too just as they would with any gas or liguid, but if you look at the fact that you reside on a sphere you should be able to see that they are spinning the same direction. Some people need to imagine theirselves standing on the bottom of their own feet. Clockwise in the north IS counter clockwise in the south. Look at it as if two toilets were connected."

                Now, I like a good standpoint argument. It doesn't, just looks like it does. At least he goes with clockwise in the North.

                Prof

                Comment


                • #9
                  Originally posted by highsea
                  ^^^ Prof, depends on the drain.

                  Actually, you can make it go either way above or below the equator depending on the shape of the sink and drain. Coriolis forces are irrelevant to sink drains.

                  But the coriolis forces are opposite, so storm rotations reverse.
                  What he said. Also depends on any motion the water starts with. Even the slightest bit of rotation in either direction will cause it to swirl in that direction. I've tested it many times, and it can go either way.
                  I enjoy being wrong too much to change my mind.

                  Comment


                  • #10
                    Originally posted by Prof View Post
                    There seems to me that there is little agreement about this. Checked around the Web. Found a guy who agrees with you. Found a guy who thinks the flow directions are opposite but that in the Northern hemisphere it's counterclockwise. In my drain it's clockwise; Bammy is south, but not that south. Some people think that the coriolis affect doesn't have anything whatever to do with small systems, some say that it does. I suspect that it does, just not very much. I have faith that there is a right answer.
                    Northern Hemisphere is CCW, Southern is CW. So your drain is opposite a large scale weather system, for the reasons I mentioned.

                    http://www.nasa.gov/worldbook/hurricane_worldbook.html

                    Tornadoes in the NH occasionally go CW, but usually CCW. Again, it's a comparitively small sytem and local conditions can overcome the weaker coriolis effect.
                    Originally posted by Prof View Post
                    I like this one:

                    "If the spin did seem the opposite or appear so. I believe the coriolis force could affect small systems too just as they would with any gas or liguid, but if you look at the fact that you reside on a sphere you should be able to see that they are spinning the same direction. Some people need to imagine theirselves standing on the bottom of their own feet. Clockwise in the north IS counter clockwise in the south. Look at it as if two toilets were connected."

                    Now, I like a good standpoint argument. It doesn't, just looks like it does. At least he goes with clockwise in the North.

                    Prof
                    Sounds good at a superficial level, but it's not right. :)
                    "We will go through our federal budget – page by page, line by line – eliminating those programs we don’t need, and insisting that those we do operate in a sensible cost-effective way." -President Barack Obama 11/25/2008

                    Comment


                    • #11
                      toilets vortex is a bad example, they can spin either way depending how bowl and flushing sys. is build. only gravity vortex (sink, bathtub) rotate in direction depending on position relative to equator.
                      iirc we already had this discussion few years back, and glyn iirc confirmed, in Kenya water does drain straight.
                      "Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote!" B. Franklin

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                      • #12
                        Three & a tiger for Omon!

                        Prof

                        Comment


                        • #13
                          ^^^ never mind it's complete nonsense, lol.

                          Gravity works the same way all over the planet. It doesn't "reverse" at the equator. Drains swirl in Kenya just like anywhere else.

                          Sorry Omon. :P
                          "We will go through our federal budget – page by page, line by line – eliminating those programs we don’t need, and insisting that those we do operate in a sensible cost-effective way." -President Barack Obama 11/25/2008

                          Comment


                          • #14
                            Originally posted by highsea View Post
                            ^^^ never mind it's complete nonsense, lol.

                            Gravity works the same way all over the planet. It doesn't "reverse" at the equator. Drains swirl in Kenya just like anywhere else.

                            Sorry Omon. :P
                            sure it does, drains do spin differently, it is a fact, so i guess it does reverse.
                            as for kenya, to be honest i was surprised to hear that it does drain straight, but that it what was said before, i'm trying to find that thread, so far no luck.
                            "Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote!" B. Franklin

                            Comment


                            • #15
                              Originally posted by omon View Post
                              sure it does, drains do spin differently, it is a fact, so i guess it does reverse.
                              as for kenya, to be honest i was surprised to hear that it does drain straight, but that it what was said before, i'm trying to find that thread, so far no luck.
                              Glyn had a pre-existing condition. :))

                              Here, I'll let snopes explain it to you:

                              snopes.com: Coriolis Force Effect on Drains
                              "We will go through our federal budget – page by page, line by line – eliminating those programs we don’t need, and insisting that those we do operate in a sensible cost-effective way." -President Barack Obama 11/25/2008

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