sábado, setembro 22, 2007
Splash and plop
'What could be more commonplace than the splash you hear when you throw a pebble into the water, often accompanied by a spray of water ?
But sometimes, instead of a splash, you hear just a little plop, and the pebble slips into the water practically without disturbing the surface [...]
the speed of impact of the pebble must exceed a certain threshold before you hear a splash, produced by closure of the air cavity caused when the pebble enters the water [...]
the value of the speed threshold is dependent on the surface of the pebble. [...] a hydrophilic marble [...] produces a small plop, even at high speed, whereas a hydrophobic marble [...] produces a large splash irrespective of the speed of impact.'
research eu, June 07
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But sometimes, instead of a splash, you hear just a little plop, and the pebble slips into the water practically without disturbing the surface [...]
the speed of impact of the pebble must exceed a certain threshold before you hear a splash, produced by closure of the air cavity caused when the pebble enters the water [...]
the value of the speed threshold is dependent on the surface of the pebble. [...] a hydrophilic marble [...] produces a small plop, even at high speed, whereas a hydrophobic marble [...] produces a large splash irrespective of the speed of impact.'
research eu, June 07
