Sound and Its Properties

The process by which sound travels through a medium.

Regions of high pressure created by the vibrating object pushing air particles together.

Regions of low pressure created by the vibrating object pulling air particles apart.

The substance through which sound travels, like air, water, or solids.

Vibrations that produce sound, such as vocal cords or a stretched rubber band.

The number of air particles in a given volume.

The back and forth movement of an object, creating changes in air pressure that result in sound.

Sound travels through a medium by creating alternating regions of high and low pressure called compressions and rarefactions respectively.

The distance between two consecutive compressions or rarefactions in a sound wave.

The number of compressions or rarefactions that pass a fixed point in one second.

One complete cycle of a wave (from maximum compression to maximum rarefaction and back).

The time it takes for one complete oscillation of a wave.

The SI unit of frequency, named after Heinrich Hertz.

The phenomenon where a sound wave's properties change as it enters a new medium.

A characteristic of sound that determines how high or low a sound is perceived. It is directly related to the frequency of the sound wave, with higher frequencies producing higher pitches.

A characteristic of sound that determines how loud or soft a sound is perceived. It is directly related to the amplitude of the sound wave, with larger amplitudes producing louder sounds.

A sound that consists of a single frequency. It is often described as a pure tone.

A sound that consists of a mixture of different frequencies. It is often described as a complex sound, and can be pleasing to listen to.

A sound that is unpleasant to hear and often lacks a defined pattern or pitch.

The repetition of a sound wave caused by its reflection off a surface.

The time it takes for a sound wave to travel from a source to a reflecting surface and back to the listener.

The distance between a sound source and a reflecting surface.

The speed at which sound travels through a medium. (Example: in air, the speed of sound is approximately 346 m/s.)

The angle between the direction of an incoming sound wave and the normal to the reflecting surface.

The angle between the direction of the reflected sound wave and the normal to the reflecting surface.

The relationship between the angle of incidence and the angle of reflection for a sound wave. The angles are always equal.

The change in direction of a sound wave as it passes from one medium to another. For example, sound waves bend when they pass from air into water.

Sound-absorbing materials like compressed fibreboard, rough plaster, or draperies are used to reduce echoes and improve sound quality in auditoriums.

Megaphones and horns use a tube and a conical opening to reflect sound waves forward, directing sound towards the listener.

A stethoscope uses multiple reflections of sound to amplify the sound of a patient's heartbeat, allowing a doctor to hear it clearly.

Curved ceilings in concert halls reflect sound waves, ensuring sound reaches all corners of the hall evenly.

Soundboards placed behind a stage reflect sound waves, dispersing the sound evenly across the hall.

The range of sound frequencies humans can hear is from 20Hz to 20,000Hz. Children and some animals can hear higher frequencies.

Sounds below 20Hz are called infrasound. Humans cannot hear them.

Sounds above 20,000Hz are called ultrasound. Humans cannot hear them.

The ability of some animals, like bats and rats, to use sound waves beyond the range of human hearing to navigate and communicate. This is used for detecting objects and navigating in the dark.

A technique that uses high-frequency sound waves to detect flaws in metal blocks. The sound waves are reflected back from cracks or holes, revealing hidden defects.

Areas of high pressure created by the vibrating source pushing air particles together. These are part of the wave that travels through the air.

Areas of low pressure created by the vibrating source pulling air particles apart. They alternate with compressions in a sound wave.

The material through which sound travels, like air, water, or solids. It enables sound waves to propagate.

A device that amplifies sound to help people with hearing loss. It converts sound waves into electrical signals, amplifies them, and then converts them back to sound.

Metal components are essential in construction, especially for large structures like buildings, bridges, machines, and scientific equipment.

The presence of cracks or holes inside a metal block can significantly reduce its strength and affect the overall stability of a structure.