Nature of sound

Definition of Sound; Elements of Sound; Anatomy of the ears; How Sound Travels

1. WHAT IS SOUND? Sound is a form of energy. It is made when air molecules vibrate and move in a pattern called waves, or sound waves.

2. WHAT IS SOUND? A type of wave that is produced by a vibrating object and that travels through matter as a longitudinal wave.

3. WHAT IS SOUND? Sound is a longitudinal wave. Sound needs a medium to travel. Waves have amplitude (volume) frequency (pitch), wavelength (speed), etc .

4. wavelength compression rarefaction

5. For human beings, sound is one of the most important ways to communicate by: expressing himself through speech obtaining information through listening obtaining stimulation (music) WHAT IS SOUND?

6. WHAT IS SOUND? Sound allows more complex information transfer than, for example, visual impressions.

7. WHAT IS SOUND? The tools of information exchange through sound are: Throat : mouth tract for producing and modulating speech sounds Ear: for listening and analyzing sounds

8. WHAT IS SOUND? The tools of information exchange through sound are: Throat : mouth tract for producing and modulating speech sounds Ear: for listening and analyzing sounds

9. HOW DO YOU MAKE SOUND? You force air up through your voice box, or larynx Your larynx consists of two folds of tissue called vocal chords (like guitar strings)

10. HOW DO YOU MAKE SOUND? You force air up through your voice box, or larynx Your larynx consists of two folds of tissue called vocal chords (like guitar strings)

11. WHAT IS SOUND? Transmission of sound requires matter (air, liquids, solids) as transmittin g medium, unlike light which can travel through matter and space.

12. WHAT IS SOUND? Transmission of sound requires matter (air, liquids, solids) as transmittin g medium, unlike light which can travel through matter and space.

13. WHAT IS SOUND? Sound can only travel if a medium is available to transmit the compressions and rarefactions. wavelength compression

14. WHAT IS SOUND? Transmission of sound requires matter (air, liquids, solids) as transmittin g medium, unlike light which can travel through matter and space.

15. HOW SOUND TRAVELS Sound waves carry energy through a medium without moving particles of the medium along Each particle of the medium vibrates as the disturbance passes. When the disturbance passes your ear you hear the sound A common medium for sound is air, but sound can travel through many other mediums

16. The Speed of Sound All sound travels through the air at the same speed At room temperature (20 ᵒ C) sound travels through the air at 343 m/s The speed of sound is not always 343 m/s because sound waves travel at different speeds in different mediums The speed of sound depends on the characteristics of the medium that sound travels through 1. Elasticity 2. Density 3. Temperature

17. Speed of Sound: Elasticity Elasticity is the ability of a material to bounce back after being disrupted The elasticity of a medium depends on how well the medium’s particles bounce back after being disrupted In a more elastic medium the particles bounce back more quickly In a less elastic medium the particles bounce back slower

18. Speed of Sound: Elasticity The more elastic the medium, the faster sound travels Sound travels well in solids because they are usually more elastic Particles of solids do not move very far , so they bounce back and forth very quickly as the compressions and rarefaction of the sound waves pass Most liquids are not very elastic and sound does not travel well Sound travels very slowly in gases because gases are not very elastic

19. Speed of Sound: Density Density is how much matter, or mass, there is in a given amount of space, or volume. Sound travels more slowly in denser mediums The particles of dense materials do not move as quickly as those of less dense material.

20. Speed of Sound: Temperature Sound travels more slowly at lower temperatures than at higher temperatures This is because at low temperatures, the particles of the medium move more slowly At low temperatures the particles are harder to move and return to their original positions more slowly. Example: @ 20 ᵒ C  343 m/s @ 0 ᵒ C  330 m/s

21. Since the temperatures are lower at higher altitudes, sound travels more slowly at higher altitudes Speed of Sound: Temperature