• Question: Why does water go in a spiral as it goes down the plug hole?

    Asked by No longer using account, to Ashley, Bernard, Carsten, Monique on 9 Nov 2015.
    • Photo: Monique Henson

      Monique Henson answered on 9 Nov 2015:

      I *think* it’s usually to do with the shape of the sink/bath. The shape of the sink can encourage the water to move in a spiral as it goes down the plughole. Sometimes it can also be due to the motion of the water before it starts going down the plughole – if the water is a bit swirly before it goes down the plughole, the swirling will get faster and faster as the water gets closer to the centre.

      Sometimes people say that it’s because of the motion of the Earth. This can cause the water to go in a spiral, but it’s such a small effect that we don’t normally see it.

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