19 questions · 11 almanac · 0 findings

Acoustics and Sound

The physics and perception of sound.

Almanac The Blackboard Screech Isn't in the Treble
  • Which frequency range turned out to be responsible for making fingernails-on-a-blackboard sound so unbearable?
  • How did researchers isolate which parts of the sound caused the strongest discomfort?
  • What evolutionary explanation did the team propose for why this sound is so aversive?
Almanac Why Spaghetti Never Snaps Clean
  • Why does dry spaghetti almost always break into more than two pieces?
  • What role does the flexural wave released at the first break play in causing further fractures?
Almanac A Device That Politely Silences Ramblers
  • What is delayed auditory feedback, and why does it make a speaker stutter or fall silent?
  • How did the SpeechJammer device use delayed auditory feedback to interrupt someone talking at a distance?
  • What delay interval between speech and its playback is disruptive enough to silence a speaker?
Almanac An Earthworm Learns to Resonate
  • What happened when researchers subjected a live earthworm to acoustic vibration at increasing frequencies?
  • Why did the earthworm's resonant patterns match what acoustic theory predicts for a soft elastic cylinder?
Almanac Helium Changes an Alligator's Voice
  • Why does breathing helium raise the resonant frequency of vocal cavities, producing the cartoon-voice effect?
  • What question about animal vocalisation were researchers testing by putting a Chinese alligator in a helium-air mixture?
  • How did the alligator's bellow change under helium, and what did that confirm about resonance theory?