Speed of sound in medium :Some interesting examples of speed of sound

Basic sound does not travel in a vacuum because it needs a medium for vibration. Sound is produced by vibrating objects. The matter through which sound is transmitted is called the medium. So sound can travel only in medium.

Sound travels in air at the relatively slow rate of 1,087 feet per second at 0⁰ C. For every degree that the temperature rises, sound travels two feet faster per second; thus if the temperature is 30⁰ C. Sound will travel  1,087 plus 60, or 1,147 feet per second. This is about 750 miles per hour.

 The reverse is true for every degree that the temperature drops from zero sound travels two feet per second slower. If you stand near a glass jar and a rifleman, standing 500 feet away, aims at the jar and fires, the jar will smash before you hear the sound of the rifle because the bullet travels faster than sound travels. 

The speed of sound in water is 41/2 times its speed in air. Sound therefore travels about 5,000 feet, or nearly a mile per second, in water. This has enabled scientists to determine the depth of the ocean.

 Small vibrating diaphragms on the bottom of a ship are sounded and this sound and this sound are transmitted through the water to the bottom of the ocean, from which it is then reflected.

 A sensitive recording device records the time elapsed between the sound of the gong and its echo. It is only a question of dividing by 2 and multiplying by approximately 5,000 to get the depth of the ocean at that point.

For example: four seconds after the gong has sounded the echo is heard. The depth of the ocean at this point is therefore 2 times 5,000 or approximately 10,000 feet.

Some interesting examples of the speed of sound

Examples of the speed of sound in the air are numerous. Thunder is the noise of lighting they occur simultaneously. We see the lighting first and then we hear the thunder.

In the air, sound travels a mile in about five seconds, so if the thunder comes ten seconds after the lightning, the storm is approximately two miles away. The speed of light is so great that may be called instantaneous in this example.

Another interesting example; watch a carpenter hammering from a distance, of say 200 feet or so, and you will hear the blow of his hammer the instant that the hammer is upraised since the sound travels more slowly than the light.