Sound is the energy produced by vibrations. When an object vibrates, sound waves travel through the air and reach a person's ears. Sound Waves are longitudinal waves (waves where the displacement of the medium is in the same direction as or the opposite direction to the direction of propagation of the wave) that can only move via air. That means sound cannot be heard in space, and are more likely to be heard underwater than in the atmosphere. The speed of sound is much slower than the speed light at 343 meters per second, which is why lightning in a thunderstorm is always seen before a clap of thunder.
The volume of the sound being heard depends on the height the crests of the sound waves. The volume of sounds are measured by decibels (dB):
|Number of decibels (dB)||Comparable to|
|10||Needle hitting a flat surface|
|100||1 meter away from loudspeaker|
|Threshold of pain (130 dB)|
|300||Krakatoa eruption (loudest recorded historical sound)|
|1,100||The creation of a black hole larger than the observable universe|
As a reminder, article comments are only for discussions on how to improve the article. Please direct other comments to a user's talk page. Please be formal and do not use excessive uppercase. Please be advised you may receive an automatic block if you break the article comments policy. For information regarding what is acceptable/not acceptable in article comments, please message Joey (talk), Natalia (talk), ynoss (talk), or Daniel (older account/talk).