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The Cause of the Formation of Meanders in the Courses of Rivers and of the So-Called Baer’s Law
August 19, 2012 6:21 PM   Subscribe

Einstein described the "Tea Leaf Paradox" (more) to explain Baer's Law of erosion.

It is the cause of leaf and colloidal clustering in stirred fluids.
posted by Algebra (9 comments total) 10 users marked this as a favorite

 
So, which one of those guys is imaginary?
posted by MustardTent at 6:37 PM on August 19, 2012


Not to sound like a snob, but would there happen to be English versions of these videos?
posted by surazal at 6:44 PM on August 19, 2012


Why does physics make so much more sense in Russian and accompanied by Zappa?
posted by cmoj at 7:12 PM on August 19, 2012


would there happen to be English versions of these videos?

There are English subtitles you can turn on.
posted by howfar at 7:52 PM on August 19, 2012


howfer: I now feel somewhat dumb for forgetting that the CC button was there. Thank you. :^)
posted by surazal at 8:14 PM on August 19, 2012


It probably also has something to do with why a wirbelrohr (aka, the Ranque-Hilsch Vortex Tube) works.
posted by Joe in Australia at 9:04 PM on August 19, 2012


The Zappa fit quite well, and this was very well explained.

I can't help but think I the only one that was suddenly freaked out when he wiped away only some of the writing on that 10th's story window.
posted by chemoboy at 9:12 PM on August 19, 2012


OK, so:

If you swirl tea in a tea cup, pressure builds up on the outside (obvious, since the waterline rises - the middle sinks to keep the volume the same).

BUT, right next to the cup, "friction" (viscous interaction) means that layer of tea is travelling slower, and therefore has lower pressure.

SO, the high-pressure tea at the top edge pushes downwards to the low-pressure tea at the bottom edge.

BUT, the tea cannot compress (liquids are incompressible), so tea that was at the bottom gets pushed inwards to lower pressure, and finally upwards again once it gets to the middle (where the water is effectively still, so it's all the same pressure).

Tea leaves are heavier than water, so they sink to the bottom, and collect where the water all comes together before rising - at the center.

******

I'm truly, honestly amazed it took Einstein to figure this out. It just doesn't seem like much of a logical puzzle, once laws of fluid dynamics are rudimentally known.
posted by IAmBroom at 9:17 AM on August 20, 2012


I'm truly, honestly amazed it took Einstein to figure this out. It just doesn't seem like much of a logical puzzle, once laws of fluid dynamics are rudimentally known.

Hindsight is 20/20...
posted by Sangermaine at 10:48 AM on August 20, 2012 [2 favorites]


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