Anonymous asked: This old tale of how water swirls different ways when poured out of a funnel on different sides of the equator has been bugging me. I know hurricanes spin opposite directions, but I've also heard some disputes about the funnel story. That its about how you pour rather than anything else. And of course I know that toilets don't swirl opposite ways if you carry them across because the direction of the swirl is dictated by the design of the commode.
Hah oh, anon. I’m really sorry this is bugging you, but you never really asked a question, so I’m a bit confused as to what you would like to know specifically. I’m assuming you want to know if the water does indeed swirl in opposite directions when poured out of funnels on different sides of the equator. Yes and no - when applied to sinks and/or toilets, this is not usually true. When this is applied to basins, and funnels, as you mentioned, the findings are a little of both yes and no, [leaning more towards yes] due to a number of variables. And, yes, you were correct that hurricanes do spin opposite directions due to the Coriolis effect.
To quote my main source here, “Now, all that said, the Coriolis effect does play a role. It’s just really tiny relative to all these other effects. It’s about 10 millions the size of the effect of gravity. So, if you have a perfect basin, with completely still water, then the Coriolis force will make the water swirl opposite directions in the two hemispheres. This was demonstrated by Ascher Shapiro, a researcher at MIT in 1962. You can see the Straight Dopetalk about this topic, or detailed information from Alistair Fraser.”
I hope this answered your question, or at least put your irritation with the issue at ease.