SOUNDBY: GROUP LOUSY

• Dhass• Dixon• Chris• Nic

CONTENT

• Introduction• Characteristics of Sound• Doppler Effect• Quality of Sound• Music

INTRODUCTION

In physics, sound is a vibration that propagates as a typically audible mechanical wave of pressure and displacement, through a medium such as air or water (longitudinal wave).

CHARACTERISTICS OF SOUND

Sound waves have frequency; that is, the pitch of sounds goes up or down. The SI unit of frequency is called a Hertz, often written as Hz.

The amplitude of a sound determines its volume (loudness). Tone is a measure of the quality of a sound wave. Sound travels the fastest in solid, second in liquid, slowest in gas. The speed of sound in air is 343.2m/s

• Frequency is dependent on wavelength and the speed of sound. It is calculated with the following equation:

DOPPLER EFFECT The Doppler Effect is the change in frequency of a wave for an observer

moving relative to its source. It is named after the Austrian physicist Christian Doppler, who proposed it in

1842 in Prague, Czech. When the source of the waves is moving toward the observer, each

successive wave crest is emitted from a position closer to the observer than the previous wave. Therefore, each wave takes slightly less time to reach the observer than the previous wave. Hence, the time between the arrivals of successive wave crests at the observer is reduced, causing an increase in the frequency.

QUALITY OF SOUND

In physics, timbre, also known as sound quality, is the quality of a musical note, sound, or tone that distinguishes different types of sound production, such as voices and musical instruments, string instruments, wind instruments, and percussion instruments.

Timbre is what makes a particular musical sound different from another, even when they have the same pitch and loudness.

MUSIC• Different frequencies create different sounds, high

frequencies soundvery ‘sharp’ while low frequencies sound very ‘heavy’.

• This is the reason to why we have music equalizers, so we can hear various frequencies at the same time.

ANY QUESTIONS??