Friday, August 2, 2013

Timescale is Everything!

In my last post, I waxed about my field of rheology in an attempt to show that the boundary between solids and liquids is fuzzier than you might think.

One other thing that rheology teaches you to appreciate is the importance of timescales. To rheologists the "pitch-drop experiment" is exciting; the difference between something that flows and something that doesn't is patience.

In fact, there is widely used dimensionless number called the Deborah number named after the prophetess Deborah, who said "The mountains flowed before the Lord".

Presumably "the Lord" works on much longer timescales.

All this is a long prelude to some amazing videos by the Slow Mo Guys. They film things squishing, popping, dropping or exploding, with a high-speed camera, and set it to music. The result is beauty and a deep appreciation for everyday phenomena that we miss because we sense and process visual data at "faster" time scales.

Here are specific links to a few that I really enjoyed: bubble bursting, underwater bullets, exploding water-melons and rubber bands, droplet collisions, etc.

Heck! Check them all out.

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