Question

Explain the pathway of sound and how sound is produced. (pages \(317-18,320)\).

Short answer

Sound is produced when an object vibrates, creating a mechanical wave of oscillating pressure which travels through a medium like a solid, liquid, or gas. In air, sound travels as longitudinal waves, while in different media, the speed and attenuation of sound waves vary. Sound is detected by the human ear through a complex structure comprising the outer, middle, and inner ear. The outer ear receives the sound waves which cause the eardrum to vibrate, transferring these vibrations through the middle ear's ossicles to the inner ear's cochlea. Tiny hair cells inside the cochlea detect the vibrations and convert them into electrical signals, which are sent to the auditory nerve and eventually processed as sound in the brain.

Step-by-step solution

Define Sound

Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, and is composed of frequencies within the range of human hearing.

Sound Production

Sound is produced when an object vibrates. This vibration disturbs the particles in the surrounding medium (solid, liquid, or gas), causing them to vibrate as well. This creates a chain reaction of adjacent particles displacing one another, forming a wave of oscillating pressure known as a sound wave.

Sound Propagation

Sound waves propagate through a medium by transferring energy from one particle to another. When a particle is displaced by the vibration of an object, it transfers energy to the adjacent particle, which then displaces the next particle in the chain, and so on. This continues until the wave reaches its destination. The speed at which sound propagates depends on the density and elasticity of the medium.

Sound Transmission through Air

In air, sound travels as longitudinal waves, meaning that air particles move parallel to the direction of the wave. As a vibrating object compresses the air particles nearby, they move closer together, forming regions of higher pressure called compressions. Similarly, particles further away from the source of vibration form regions of lower pressure called rarefactions. The continuous movement of particles between compression and rarefaction results in the propagation of the sound wave.

Sound Transmission through other media

Sound can also travel through various other media, like solids, and liquids. In each case, the principle of particle displacement remains the same. The speed and attenuation of the sound wave varies depending on the medium's characteristics.

Sound Detection by the Human Ear

The human ear detects sound via a complex structure composed of the outer, middle, and inner ear. When sound waves reach the outer ear, they travel through the ear canal and strike the eardrum, causing it to vibrate. These vibrations are then transferred to three tiny bones in the middle ear called the ossicles, which increase the amplitude of the vibrations and transmit them to the cochlea in the inner ear. Inside the cochlea, tiny hair cells detect the vibrations and transform them into electrical signals, which are then relayed to the auditory nerve and ultimately reach the brain, where they are processed as sound.

Summary

Sound originates from a vibrating object, which disrupts the particles in a surrounding medium, creating a sound wave. This wave propagates through the medium by transferring energy from particle to particle until it reaches our ears. The human ear is then responsible for detecting sound waves, converting them into electrical signals, and transmitting these signals to the brain for interpretation. The process of sound production, travel, and detection helps us understand the world around us and communicate with each other.