Sound Meets Salt
You’ll want to turn down your speakers for this one.
Sound is an amazing thing. Though nearly always invisible, it has an incalculably great influence on almost every aspect of our lives. As any 8th grade know-it-all can tell you, sound is nothing more than a series simple pressure waves created by a vibrating source. As with any kind of wave, strange and fascinating things can happen when two or more wave systems come together.
The video above shows how different tones, or frequencies, manifest different complex interference patters when produced by a vibrating metal source. Spots of high energy where waves meet and build each other vibrate rapidly and bounce the salt away, while salt collects in the places where waves meet and cancel each other out. [via]
