Drops of water sometimes bounce off a pool of water instead of coalescing. Fluid dynamicists have been fascinated by this behavior since the 1800s, but it was Couder et al. who explained that these droplets can bounce indefinitely as long as the thin air layer separating the drop and pool is refreshed by vibrating the pool.
In this video, Destin from SmarterEveryDay teams up with astronaut Don Pettit to film the phenomenon in beautiful high-speed.
Watch: https://www.youtube.com/watch?v=KJDEsAy9RyM
It turns out that the cello produces just the right frequencies to create a cascade of bouncing water droplets.
And since Destin mentions the equation of Collisional Kinetic Energy (CKE), I have to mention that a perfectly elastic collision is defined as one in which there is no loss of kinetic energy in the collision. An inelastic collision is one in which part of the kinetic energy is changed to some other form of energy in the collision.
Paper:
https://www.researchgate.net/publication/7837945_From_Bouncing_to_Floating_Noncoalescence_of_Drops_on_a_Fluid_Bath
h/t FYFD
https://www.youtube.com/user/fyfluiddynamics
#physics #science #noncoalescenceofdrops #fluiddynamics
The surface tension of water affects life's function on a fundamental level. Without surface tension, the water droplets skating across the standing water would not happen. For example, add a surfactant to the water and see what happens. I guess the 'skating effect' of water is roughly equivalent to: (one over pie r squared of the water droplet) so obviously it is only observed on a relatively small scale (at least here on earth in gravity = one (g=1). Any true outdoorsperson knows about this wondrous curiosity! (hint... hint) : )
ReplyDeleteOOps... I think that would be: (one over pie r cubed)
ReplyDeleteThanks for sharing Miss Corina.....:-)....
ReplyDelete