Why does water form swirly patterns?
I was swimming in the sea recently and noticed that the water had a swirling effect. Right next to where I was standing or any pillars in the water, it was really pronounced and we were trying to work out why it was happening.
Dave - You'll certainly see some swirling effects if you've got the water flowing past a column due to a tide - the wake formed can look quite swirly. You can also get whirlpools created by tides flowing round corners and water being sucked underneath, which form what used to be called maelstroms.
Chris - There's some incredible youtube footage of one off the west coast of Scotland Dave - And there's some quite serious ones in the Strait of Messina that I sailed past once too. Chris - Not into them I hope!