Recent content by AdrianMay

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    Why does bathwater in a plughole spin AT ALL

    @Grinkle It's a counterargument because I can keep the vortex going forever by topping up the bucket. When a fluid shears (parallel layers sliding against each other), it experiences friction that opposes the shear. That means the vortex must slow down. But it doesn't. Therefore, something...
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    Why does bathwater in a plughole spin AT ALL

    @Grinkle You're not distinguishing buckets with holes from buckets without. Your funnel has a hole. I said that buckets with holes can turn under recoil. In a bucket without a hole, I expect the currents to die away. Edit: Your marble will come to rest before long. Edit 2: It's losing velocity...
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    Why does bathwater in a plughole spin AT ALL

    @Grinkle. 1. It doesn't matter how viscous the stuff is. Yes it will eventually go all the way to zero. My point is that the vortex can keep going for a million years if you keep pouring water in the top despite not injecting angular momentum in the process. If we propose that the only reason...
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    Why does bathwater in a plughole spin AT ALL

    @Nidum Or the way a pea can roll off the back of a spoon?
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    Why does bathwater in a plughole spin AT ALL

    @Grinkle please see #25. That original angular momentum should decay by viscous friction. What keeps it going?
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    Why does bathwater in a plughole spin AT ALL

    @Dale My argument about friction in #25 supersedes that one. Let's imagine we snugly fit a corkscrew into the drainpipe. At this point, nobody would be mystified at all. We'd say that the device converts gravitational potential energy into kinetic energy, that the latter goes round in circles...
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    Why does bathwater in a plughole spin AT ALL

    You hit the nail on the head about friction. Why ignore it? It's the clinching argument against the pre-existing currents theory. I can keep that vortex going forever by putting water in the top (being careful not to inject angular momentum of course) but I can see from the dramatic shear in the...
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    Why does bathwater in a plughole spin AT ALL

    @Tom.G I can draw a conclusion there. If I filter your results on numbers greater than 1, I see that the swirl goes the way you pushed it. If I add the top two 1s to make 2, I get a result that's inconvenient for what I said above (I seem to have predicted that the water would reach a favourite...
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    Why does bathwater in a plughole spin AT ALL

    Wow! Lots of responses. Let me work through them: @RobertF I agree with you if there's a closed vessel involved like a jug or a wine bottle, but the drainpipe from my bath just opens into the garden somewhere near another drain in the ground. The air can return via the bathroom window. Both...
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    Complaint Rule prohibiting personal theories

    Helmholtz's 1858 paper is a[SIZE=16px] PDF on Google under the name I gave. I like your sarcasm, but I hope nobody misinterprets it as trolling. That would be incongruous in a mentor. Thinking more about that rule, in this case it seems to be having the undesirable effect of stifling a...
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    Complaint Rule prohibiting personal theories

    But if the journal already peer reviewed and published it, what is PF for? It's for amateurs to get their brain around that stuff of course. But isn't an amateur's attempt to interpret high end science a theory in itself? Surely, you and me can only theorise about what they might mean by a...
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    Complaint Rule prohibiting personal theories

    As it happens, I didn't know that rule, and I find it quite absurd. Aren't all theories personal at the moment of their conception? At what moment does a theory become official enough to be seemly in this temple of doctrine? Take the newly found dark matter for instance. Did that make the grade yet?
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    Why does bathwater in a plughole spin AT ALL

    Well I did try to Google for an answer, but I just get stuff about whether it goes clockwise or anticlockwise. So I apologise for resorting to personal theories. Feel free to illuminate us with the official answer.
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    Why does bathwater in a plughole spin AT ALL

    I agree with everything @Nidum said, but it still doesn't explain why the water spirals.
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    Why does bathwater in a plughole spin AT ALL

    > What do you mean when you say it doesn't look that way to you? I'm referring to my own previous paragraph.
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