Understanding Sound: Characteristics and Propagation

Sound is a mechanical wave transmitted by vibrations in a medium, such as air, water, or solids. It requires a medium to travel, making it impossible for sound to propagate in a vacuum.

Sound travels as longitudinal waves where particles oscillate parallel to the wave direction. Its speed depends on the medium's elasticity and density—faster in solids, slower in gases.

Frequency, measured in Hertz (Hz), dictates sound's pitch. High-frequency sounds have a high pitch, like a whistle, whereas low-frequency sounds have a low pitch, like a drum.

Amplitude of sound waves determines the loudness. Higher amplitude means a louder sound. Interestingly, the smallest amplitude a human ear can detect is known as the threshold of hearing.

Humans can hear frequencies from about 20 Hz to 20,000 Hz. Sounds beyond this range exist but are inaudible to us, like infrasound (below 20 Hz) and ultrasound (above 20,000 Hz).

Sound intensity diminishes with distance, following the inverse square law. It means doubling the distance from the source decreases the intensity to a quarter of its original level.

A sonic boom occurs when an object moves faster than sound, compressing waves into a shock wave. It's not just heard once; it's a continuous effect as long as the object exceeds the speed of sound.

The loudest natural sound on Earth is the Krakatoa eruption in 1883, heard 3,000 miles away, rupturing eardrums of sailors 40 miles from the blast.