Down the drain
Back home, all of this has almost nothing to do with your bathtub drain, which creates another spiral shape.
There is a popular myth, though, owing to the rotational direction of a hurricane, that says the water in bathtubs rotates a certain direction in the Northern Hemisphere.
It's not true.
The Coriolis effect does not determine which way the water swirls in your house. The effect is too tiny to impact such a minor, localized process, all experts agree.
That means water is free to swirl in either direction in tubs in both hemispheres. Which way it goes is determined by the geometry of a particular basin or, if things are perfectly aligned and balanced, then by chance.
Never say this blog does not keep you up to date with vital scientific information.