2. A vibration :
• is a complete back and forth motion of an object, as in the
longitudinal waves.
What is sound?
• Your brain interprets the vibrations in the air as sounds.
10/18/2016MR / ISMAIL ETMAN 2
3. is a longitudinal wave that caused by
vibration travels through a medium.
Sound wave travels by vibrating the particles of the
medium.
The particles of the medium do not move with the sound
wave, It just vibrates back and forth along the path that
the sound wave travel.
Sound wave moves through solid faster than water,
faster than air.
Sound wave does not moves through the vacuum.
Because, There is no particles in the vacuum. 10/18/2016MR / ISMAIL ETMAN 3
5. is how high or low you think a sound is.
- It depends on the frequency and the wavelength of the
sound.
Higher
frequency
shorter
wavelength
higher
pitch
10/18/2016MR / ISMAIL ETMAN 5
6. is measure of how well a sound can be heard.
- It depends on the amplitude of the sound wave.
- &
- The unit of measuring is decibel (dB).
1 bel = 10 decibels.
greater
amplitude
louder sound
smaller
amplitude
softer
sound
10/18/2016MR / ISMAIL ETMAN 6
7. • The maximum distance that the particles of a wave's medium
vibrate from their rest position.
10/18/2016MR / ISMAIL ETMAN 7
8. • Is the change of the observer frequency when the sound source, the
observer, or both are moving.
10/18/2016MR / ISMAIL ETMAN 8
9. • Two fire trucks with sirens on speed towards and away from an
observer as shown below.
a) Which truck produces a higher than normal siren frequency?
__________
b) Which truck produces a lower than normal siren frequency?
___________
10/18/2016MR / ISMAIL ETMAN 9
10. 1.Circle the letter of each statement about the Doppler Effect that
is true.
a. It occurs when a wave source moves towards an observer.
b. It occurs when an observer moves towards a wave source.
c. It occurs when a wave source moves away from an observer.
d. It occurs when an observer moves away from a wave source.
2.The ______________ of sound is directly related to its intensity.
a. Pitch
b. Loudness
c. Amplitude 10/18/2016
MR / ISMAIL ETMAN
10
11.
12. Sound travels fastest through solids,
Slower through liquids,
Slowest through gases.
Higher temperature of a medium,
greater speed of a sound through it.
10/18/2016MR / ISMAIL ETMAN 12
13. • The bouncing back of a wave when the wave hits the barrier.
- Smooth and hard surface is the best reflected surface.
•
10/18/2016MR / ISMAIL ETMAN 13
14. - A rough wall will absorb sound better than a smooth wall will.
- A soft materials absorb sound better than hard materials do.
10/18/2016MR / ISMAIL ETMAN 14
15. - Rough materials reduce echoes by scattering sound waves.
the use of reflected sound waves to find objects.
- Examples : of using echolocation.
Sound navigation and ranging ( sonar ).
Some animals ( bats ,….).
10/18/2016MR / ISMAIL ETMAN 15
16. • happens when two or more waves overlap and combine to
form one wave.
two sound
waves
nearly equal
frequencies
Constructive
Interference
Destructive
Interference
not quite
equal
frequencies
beats
10/18/2016MR / ISMAIL ETMAN 16
17. Constructive Interference:
When waves overlap and combine to form
a wave with a larger amplitude.
Produce a louder sound.
Destructive Interference:
When waves overlap and combine to form
a wave with a smaller amplitude.
- Produce a softer sound.
Examples: headphone.
10/18/2016MR / ISMAIL ETMAN 17
