DEFINITION OF SOUND
• Sound is longitudinal wave which spreads in the form of comprsseion and rarefaction , with spreading direction equals to its vibration direction
Properties of sound
1. Sound wave is produced by vibration object.
2. Sound wave need medium to spread.
3. Sound wave can spread in the solid , liquid , and gas.
VELOCITY OF SOUND
• The distance travelled by sound wave in every time unit.
Sound velocity is formulated as follow : SOUND VELOCITY = DISTANCE / TIME
• Based on the experiment result of Moll and Van Beek is obtained summary that the higher air temperature , the faster sound velocity , on the contary the lower air temperature , the smaller sound velocity.
In this case holds the formula : v= vo + 0,6 t
KIND OF SOUND BASED ON FREKUENSI
Infrasound : >20 Hz
Audiosound :20Hz-20.000Hz
Ultrasound :<20.0000Hz
Tone
• Is a sound that frequency of its vibration is certain or the number of vibration in every second in same and constant.
• Usually produced by musical instruments. Such as guitar , flute , and gamelan.
• Tone depend on frequency of sound source: the higher frequency of sound source , the higher also sound tone produced.
Fricative
• Is the sound that is frequency is not regular. Example : sound of leaves blow by the wind , the sound of waterfall , the sound of booming wave ,etc.
Bang
• The fricative sound that is very loud.
• Example :
1. Sound of canon
2. The sound of bomb
3. And sound of thunder
POWER OF SOUND
• The power of sound depends on amplitude : the larger its amplitude the stronger or louder the voice , the smaller its amplitude then the weaker also the sound.
Color of sound
• Is combination of 2 sound that have the same frequency but is heard different.
• Example :
1. A man singer and a woman singer make duet to sing a song , but we can hear different of both.
2. Tone c in guitar its frequency is same with the tone c in piano, but the color of sounds is different.
Marsenne’s Law
1. The frequency of string depends on the length of string. Long string has low frequency , short string has high frequency.
2. The frequency of string depends on the section area of the string .Thick string has low frequency thin string has high frequency.
3. The frequency of strings depends on string tension .The tense (tight) string has high frequency , the loose string has low frequency.
4. 4. The frequency of string depends on density of the string. String with large density has low frequency.
Resonance
• Commonly resonance can maened as the phenomenon of follow to vibrate a body that has the same frequency.
THE LAW OF SOUND REFLECTION
Incident sound , normal line , and reflected sound lie on one flat plane.
Incident angle is equal to reflected angle.
The kinds of reflected sound
Reflected sound that strengthen original sound.
Reverberation
Echo
Sound velocity can be determined by using sound reflection.
v = 2s/t
SEVERAL USE SOUND REFLECTION
1. Determining sea dept.
2. Determining location of fish region.
3. Making geophysics survey.
4. Detecting defact and crack in metal.
5. Measuring metal thicknes.
6. Detection position of baby in pregmenancy
