10 interesting facts about sound

  1. The sound of a whale song can travel a distance of 800 km.
  2. Sound with frequencies of less than 20 Hz is known as infrasound. If a sound has a frequency that exceeds 22,000 Hz it is called ultrasound.
  3. Sound is a travelling wave which is an oscillation of pressure transmitted through a solid, liquid, or gas.
  4. For humans, hearing is normally limited to frequencies between about 12 Hz and 20,000 Hz (20 kHz), although these limits are not definite. The upper limit generally decreases with age.
  5. Dogs can perceive vibrations higher than 20 kHz.
  6. In the air sound travels at the speed of about 335 metres(6100 feet) a second.Sound travels about 4 times as fast in water as it does in air.
  7. The speed of sound is approximately 343 m/s (1,230 km/h; 767 mph).
  8. Sound is transmitted through gases, plasma, and liquids as longitudinal waves, also called compression waves.
  9. The accepted units for sound pressure are metric, Newton per one square meter (N/m2).
  10. Sound waves are invisible because the human eye can’t see pressure waves. But an oscilloscope can detect and show the shape of sound waves very accurately.