Sound is produced by vibration and requires a medium to travel through. The document discusses the definition of sound, the speed of sound in different mediums, experiments measuring the speed of sound, factors affecting sound like frequency and amplitude, resonance, and reflection of sound. It provides examples and formulas for calculating speed of sound based on distance and time, using the relationship speed = distance/time. Human hearing is limited to sounds between 20-20,000 Hz.

1. Disusun oleh: Noviyanti

2. Definition of Sound
Sound is a result of vibration.
Every vibration produces sound,
but human hearing is limited.
Sound needs a medium to
propagate.

3. The requirements of audible sound
a. The availability of the source of
sound (vibrating object);
b. The availability of a medium;
c. The availability of ears (hearing
instruments)

4. 1.Speed of Sound
Speed of sound is the distance to be
covered starting from the source
of the sound to the receiver within
a certain time interval.
The speed of sound depends on the
density of the medium. The best
medium is solid, while the worst is
gas.

5. Formula the speed of sound
v = s/t
Where:
v = speed of sound (m/s)
s = distance from the source of
sound to the receiver (m)
t = time needed to cover the
distance (s)

6. Example:
Edo saw a lightning. 5 second after that he heard the
sound of thunder. If the speed of sound in the air
was 350 m/s, what was the distance between the
place where Edo was standing and the place of the
lightning?
Solution :
Given : v = 350 m/s
t = 5s
Asked : s ....?
Answer : s = v . T = 350 m/s X 5 s = 1750 m
Hence, the distance from the place in which Edo was
standing to the place of the lightning whose 1,750 m

7. 2.Experimen to measure the speed of Sound
• In 1934,two dutch physicist named Moll and Van
Beek conducted an experiment to measure the speed
of sounds in the air by shooting a bullet from a
cannon.One of them acted as the shooter and the
other one acted the observer with time recorder.
• From the above experiment.The speed of sounds in
air depends on air temperature.The higher the air
temperature is,the faster the speed of sound in the
air will be.On the other hand,the lower the air
temperature is,the smaller the speed of sound in the
air will be.The speed of sound does not depend on air
pressure

8. 3.The Medium
• The medium can be in the forms of a
solid,liquid and gas.
Example :
• A boy,who is in the swimming pool,is able
to hear the sound of a collision of a
stone with the bottom of the pool.It
shows that sound can also propagate in a
liquid.

9. 4.Limit of human hearing
• Humans are only able to hear sound with a frequency
between 20 to 20.000 Hz so object which vibrate less than
20 Hz and or more than 20.000 Hz in one second cannot be
heard by human’s ears.
• Based on the limits of human hearing,sounds can be
classified into 3 categories they are as follow :
a) Infrasonic,which is sound with a frequency below 20
Hz.This sounds can be heard by crickets and dogs.
b) Audiosonic,which is sound with a frequency within 20 to
20.000 Hz.This is sound can be heard by human.
c) Ultrasonic,which is sound with a frequency above 20.000
Hz this sound can be heard by dogs and bats.

10. • Ultrasonic can be used for :
a) Glasses for blind people
b) To Measure the depth of sea
We can determine the depth of the sea
(d),if the speed of sounds (v) and the
time interval (t) between the
transmitting and receiving of pulse are
known
D = vt/2 or d = ½ vt

11. c. Medical instruments
Ultrasonic sound is also useful in the
medical field, for example in USG
(ultrasonography) inspection.

12. Factor Affecting Sounds
1. Frequency of sound
frequency is the number of vibration in every
second it has units of vibration per second or
hearts and symbolized as Hz.
so, sound depends on the frequency of the source
of sound.
2. Intensity of sound and amplitude
amplitude is the distance of displacement.
the softness and strengthness affected by the
amplitude and can also be affected by one’s
distances from the source of sound

13. 3. Timbre or the quality of sound
timbre is two sound with the same
frequency, but heard differently.
Timbre is generated due to the
overtones acompanying the keynote.
It produce a tone which is called
the keynote.

14. Tone
Tone is a reguler sound produce by a source of sound.
Tone is a sound in which the number of its vibration in
every second is the same. A sigh is a sound in which the
number of its vibration in every second is not the same.
1. Gamut and tone interval
the comparison of the frequency of each tone is
called the tone interval. The comparison of each
individual tone interval produce the tone spacing. The
arrangement of tone based on their frequencies is
made in the formof a gamut. Such a gamut is called
diatonic.

15. 2. mersenne’s law
mersenne’s law they are follows:
a. The frequency of a vibrating string is
inversely proportional the lenght of the
string (i) a longer string will result in a
lower frequency.
b. The frequency of a vibrating string is
inversely prpotional to the square root
of the mass per unit length of the
string (p) a light string (low destiny)
has a high frequency,while heavy string
(high destiny) has a low frequency.

16. C.The frequency of a vibration string inversely
propotional to the square root of the cross-sectional
area of the string (a).a thick string has
a low frequency while a thin string has a high
frequency.
D.The frequency of a vibrating string is directly
propotional to the square root of the tension of
the string (T).A tense string (higher tension of
string) has a higher frequency,while a loose string
(lower tension of string) has a lower frequency.

17. E.Resonance
1.Understanding the resonance.
• Resonance is that two or more object
which has same frequency will follow
vibration when another object with the
same frequency is vibrating.
• The requipment of resonance are as
follows :
a. The frequency of the resonating
object has to be the same has
frequency of the source of vibration
b. The high of the air columns is odd
multiplication of ¼ wavelength.
c. The instrument have thin membranes
which are able to vibrate.

18. 2.Problem caused by resonance
• Resonance may cause problem in daily life.a
goblet can be broken when it is placed close to
a singing singer.this may happen if a goblet
(made of glass) has the same the natural
frequency as the frequency of the voice from
the singer,sounf the glass experiences
resonance and is broken.

19. 3.The advantages of resonance
A Resonance of sounds in an air column can
be use to produce sounds. People make many
kinds of musical instruments.example of such
as kind of musical instruments are the flute
guitar, drum, bedug, violin, and ketipung.

20. f. Reflection of sounds
1. The law of reflection of sound
a. The incident sound, normal line, and
reflected sound are located at the same
plane.
b. The reflected angle is the same as the
incident angle.

21. 2. Kinds of sound reflection
Echo and referberation are example of the
sound reflection. Principally, the sound
reflection can be distinguidhed into 3 types :
There are reflected sound which is reinforcing
the original sound echo and referberation.
a. Reflected sound which is reinforcing the
original sound.
b. Echo
c. Reverberation

22. 3. The advantages of sounds reflection
a. To define the speed of sound
b. To do a geophysical survei