Tone generator, a wave driver (speaker) and a metal plate attached to a speaker. First add sand to the plate then begin playing a tone. Certain frequencies vibrate the metal plate in such a way that it creates areas where there is no vibration.
A simple shopping trip goes horribly wrong.
If you want to become an actor, don't let these guys teach you
Making motorcyclists look good.
Smarter Every Day - Prince Rupert's Drops are toughened glass beads created by dripping molten glass into cold water, which causes it to solidify into a tadpole-shaped droplet with a long, thin tail. These droplets are characterized internally by very high residual stresses, which give rise to counter-intuitive properties, such as the ability to withstand a blow from a hammer or a bullet on the bulbous end without breaking, while exhibiting explosive disintegration if the tail end is even slightly damaged.
