Comments on: 230. Video of the day: viscosity or the arrow of time is reversible http://www.nonequilibrium.net/video-day-viscosity/#utm_source=feed&utm_medium=feed&utm_campaign=feed For physicts by physicists Tue, 31 Jan 2012 20:24:03 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Lubos Motl http://www.nonequilibrium.net/video-day-viscosity/comment-page-1/#comment-5837 Lubos Motl Thu, 05 Feb 2009 17:00:38 +0000 http://www.nonequilibrium.net/?p=1268#comment-5837 Haha, very funny. The reason why it looks counterintuitive is the people normally confuse chaotic motion and organized motion. The entropy growth in the system is extremely slow - you can see that the droplets don't change too quickly at the beginning, and you can predict how much they would change in 2 minutes. The systematic motion inserted into the system is non-chaotic and completely reversible, and because of the high viscosity, it doesn't strongly help the droplets to mix microscopically with the environment. So it's completely analogous to stretching a piece of rubber by a lot, and releasing it, allowing it to return to the original shape. Of course that the system will almost return where it was, and the only dissipation is the slow one that could be observed at the very beginning. Haha, very funny. The reason why it looks counterintuitive is the people normally confuse chaotic motion and organized motion.

The entropy growth in the system is extremely slow – you can see that the droplets don’t change too quickly at the beginning, and you can predict how much they would change in 2 minutes.

The systematic motion inserted into the system is non-chaotic and completely reversible, and because of the high viscosity, it doesn’t strongly help the droplets to mix microscopically with the environment.

So it’s completely analogous to stretching a piece of rubber by a lot, and releasing it, allowing it to return to the original shape. Of course that the system will almost return where it was, and the only dissipation is the slow one that could be observed at the very beginning.

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