SOUND WAVESLongitudinal

Mechanical

Speed of SoundMedium Temp. in Celsius Speed in m/s

Air

0 3311 331.62 332.23 332.84 333.4

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

Find the speed of the sound:

•10⁰C•15⁰C•28⁰C•37⁰C•39 ⁰C

Frequency of different NotesNOTES FREQUENCY

Do 256Re

Mi

Fa

SO

La

Ti

Do 512 (twice of the first one)

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?

Sound Wave Property

Property Sound

Reflection Echo, Reverberation

Refraction Change of direction

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.

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 soundb. Find the distance of the man

from the cliff.

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.

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.