2. Speed of Sound
Medium Temp. in Celsius Speed in m/s
0 331
1 331.6
Air 2 332.2
3 332.8
4 333.4
3. What have you noticed in the speed of the
sound?
•Every 1 degree Celsius
temperature rises, add 0.6
•+ 0.6 m/s for every 1
degree Celsius of air
temperature increases
4. Find the speed of the sound:
• 10⁰C
• 15⁰C
• 28⁰C
• 37⁰C
• 39 ⁰C
5. Frequency of different Notes
NOTES FREQUENCY
Do
256
Re
Mi
Fa
SO
La
Ti
Do
512 (twice of the first one)
6. Solve:
• On a warm day (Temp. 32 ⁰C).
What is the wavelength of the
note middle Do with a frequency
of 256 Hz?
• If on a given day, the note whose
frequency is 338 Hz has a
wavelength of 1.2m, what is the
air temperature?
8. ECHO: Reflection
• Reflection of Sound; Reflected on a wall
• 16 m away to hear an echo; .05s to hear
an echo
• .1 s to hear a sound from eardrum to the
brain
Example: d = vt
Find the distance of the echo if it travels
at a speed of 340m/s.
9. Solve:
• A man stands facing a cliff. The
air temperature on that day is
24⁰C. He fires a riffle and hears
the echo after 2.6 s. How far is
he from the cliff?
a. Find the velocity of the sound
b. Find the distance of the man
from the cliff.
10. Refraction: Change of direction/speed
• Sound waves are refracted away
from the Earth during day time.
• Sound waves are refracted
towards the Earth during night
time.
• Sound is more audible during
night time.
11. Quality of Sound
• Pitch and Loudness= quality (Physics)
• Pitch and Volume= timbre (Music)
• Quality- is that which make the sound the
way it sounds
• Fundamental Frequency- consists of many
frequencies sounding at the same time.
(vibrating string)
- Many frequencies sounding at the same time
in harmony.
