10 interesting facts about sound
- The sound of a whale song can travel a distance of 800 km.
- 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.
- Sound is a travelling wave which is an oscillation of pressure transmitted through a solid, liquid, or gas.
- 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.
- Dogs can perceive vibrations higher than 20 kHz.
- 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.
- The speed of sound is approximately 343 m/s (1,230 km/h; 767 mph).
- Sound is transmitted through gases, plasma, and liquids as longitudinal waves, also called compression waves.
- The accepted units for sound pressure are metric, Newton per one square meter (N/m2).
- 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.
