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30 Second video that will change your notions of fluid mechanics and surface tension. (Original Post) G_j Jul 2013 OP
K&R pscot Jul 2013 #1
seriously, but how beautiful Voice for Peace Jul 2013 #4
A lot of things happening Brother Buzz Jul 2013 #2
Video Description napoleon_in_rags Jul 2013 #3
I've seen it before... awoke_in_2003 Jul 2013 #5
Why does it take so long for plastic containers to air dry ErikJ Jul 2013 #6
No expert; greiner3 Jul 2013 #9
Youre kind of right. ErikJ Jul 2013 #13
Because the people who make them are slimy. Spitfire of ATJ Jul 2013 #10
Great post! And there are others like that available 7962 Jul 2013 #7
What sorcery is this?! nt Demo_Chris Jul 2013 #8
Really beautiful, thank you for posting it! (nt) petronius Jul 2013 #11
thanks, that was interesting Liberal_in_LA Jul 2013 #12
It proves that surface tension is only a "theory" and it's God who wants us PCIntern Jul 2013 #14


(3,992 posts)
3. Video Description
Sun Jul 21, 2013, 01:00 PM
Jul 2013
I saw this on the TV show "Time Warp" and thought that I could do that. Well it turns out that Noah and I could do it! I was a little surprised at how small the parameter space was to achieve a good series of bounces. Near the end of this clilp, you can see waves entering from the lower right. I think these are reflections of a low frequency sloshing modes set up by the initial droplet. The smallest droplet bounces off these waves and start moving off to the side. In any case it is pretty cool. The only issue is that there was some dust on the sensor (dark spots that don't move). The camera is a Vision Research Phantom v7.3 high speed video camera.

Assuming its water, really neat.


(5,214 posts)
9. No expert;
Sun Jul 21, 2013, 03:45 PM
Jul 2013

But it may have to do with the fact that glass and ceramic have smoother surfaces, whereas plastic has a less smoother surface.

This may allow water droplets to 'adhere' to the plastic surfaces and withstand evaporation better than glass and ceramic.





(6,335 posts)
13. Youre kind of right.
Sun Jul 21, 2013, 07:34 PM
Jul 2013

Q Why does plastic dry slower than glass?

A Ever wonder why Tupperware containers retain huge droplets of water after a dishwasher cycle, or why plastic cups take longer to air-dry than their glass counterparts? UW-Madison physics Professor Clint Sprott explains that two factors are at play: cohesion and adhesion.

"Cohesion is the tendency of the water molecules to attract one another and collect into a spherical droplet," Sprott said. "Adhesion is the attraction of the water molecules to the surface."

The spherical shape of a water droplet results from molecules trying to get as close together as possible. This allows for the most comfortable arrangement and a minimum energy state. When water encounters a surface, a tug of war between cohesion and adhesion causes droplets to flatten to different degrees. "The ratio of cohesion to adhesion dictates whether the water forms droplets or a thin film on the surface," Sprott said.

"The adhesion of water to clean plastic is relatively small compared to the adhesion to glass, and thus the water does not spread across the surface of the plastic as it would for glass," Sprott added.

So what does this mean for the drying time of different materials? "It takes longer for the plastic to dry since the droplets have a smaller surface area than does a thin sheet of water on glass,"

Read more: http://host.madison.com/news/local/ask/curiosities/curiosities-why-does-plastic-dry-slower-than-glass/article_31d0e21a-34df-11e1-bdb3-001871e3ce6c.html#ixzz2Zj4P5Dha



(11,841 posts)
7. Great post! And there are others like that available
Sun Jul 21, 2013, 03:38 PM
Jul 2013

Te high-speed camera used to film seemingly normal events show so much. When I first saw this one, i was amazed. There are some other great ones out there on youtube.


(25,928 posts)
14. It proves that surface tension is only a "theory" and it's God who wants us
Sun Jul 21, 2013, 07:40 PM
Jul 2013

to view this thing of beauty. It is like the "theory of aerodynamics" which doesn't exist: thousands of little angels lift up the plane by the wings and fuselage. Yes, that's how it works!

just in case.

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