SoundBy,Anish. DIX’B’

Agenda / Topics• What is Sound?•Production of Sound•Propagation of Sound

What Is Sound

What Is Sound?

• Sound is a form of energy.• We can define a sound wave as a disturbance which travels through some medium.• Sound is the term to describe what is heard when sound waves pass through a medium to the ear.• All sounds are made by vibrations of molecules through which the sound travels. For instance, when a drum or a cymbal is struck, the object vibrates.• These vibrations make air molecules move. Sound waves move away from their source (where they came from), traveling on the air molecules. When the vibrating air molecules reach our ears, the eardrum vibrates, too. The bones of the ear vibrate in the same way that of the object that started the sound wave.• These vibrations let you hear different sounds. Even music is vibrations. Irregular vibrations are noise. People can make very complex sounds. We use them for speech.• Sound is a mechanical wave.• It needs a medium to travel. It cannot travel in vacuum.• It travels in the form of waves

Sound

The Process Of Sound Travel: From A Vibrating Object To Our

Ear

Sound is made by the vibrating object

The sound energy travels through the medium (air) in the form of waves

But the particles do not

move. They just transfer

energy

The sound is picked up by

the ear

Production Of Sound

Production Of Sound• Sound is produced through vibration of an object.•Vibration means a kind of rapid to and fro motion of an object.•For example:-

Propagation Of SoundGroup member name

Propagation of Sound• Particles of the medium do not move. They just transfer energy.• Sound travels in the form of waves.• There are Two types of waves:

• Particles’ movement parallel to the direction of propagation of disturbance

• Ex:- Sound wave

Longitudinal Wave

• Particles’ movement perpendicular to the direction of propagation of disturbance

• Ex:- Light wave

Transverse Wave

Compressions And Rarefactions• When an object vibrates it creates a series of compressions and rarefactions.• Compression- region of high density of particles• Rarefaction- region of low density of particles

Medium For TravelSound

needs a medium to

travel.

Travels in the form of

waves

Can travel through solids ,

liquids & gases

Fastest in solids,

slowest in gases

Cannot travel in vacuum

Sound through Solids

Why is the speed of

sound fastest in solids?

Because in solids,

particles are close

So, direct transfer of

energy occurs

Thus, speed of sound is fastest in

solids

Sound through Liquids

Speed of sound is slower in liquids

compared to speed in solids

In liquids, particles are bit spaced

out

This is the reason of the decrease of

speed

Sound through Gases

Speed of Sound is

slowest in gases

Particles of gas are widely

spaced out

So, speed of sound is

slowest in gases

Speed of Sound In Different Media

solids(steel) liquids (distilled water)

gas vacuum0

5000

10000

15000

20000

25000

5960

1498 346 0

21456

5392.81245.6 0

m/skm/h