Homework 9: Due 3/20/07 Evaluate part of straw oboes (this is my evaluation of what you learned): Explain how stringed instruments work using the terms wavelength, frequency and wave speed. Compare and contrast stringed instruments and straw oboes (minimum 200 words).

Check with your group Does at least one member have a USB memory stick?

Late Homework Policy • • • No loss until now From now on, late homework loses 1 point per day late If you miss class where homework is due, you must get the homework to me by the next day. After that the assignment will start losing points.

Feedback on ear and eye report: • • • • Generally excellent, correct and well written descriptions.

I noted only a few typos and unclear statements in some papers, but in some I found no typos! Good job.

Varying degrees of relating the explanation of the ear and eye to sound and light.

May be ear/eye questions on next quiz, exam of final.

Review with Spacephones • Longitudinal • Transverse • Mechanical wave converted to sound wave through the vibrating diaphragm

Extend:

MacScopeII (you can add this to your notebooks in the Straw Oboes activity) Pure tones: Tuning fork, bar, quartz crucible, loon, triangle, whistle Mixed harmonic tones: Tin whistle, cow bell, straw oboes, voice

Speed of sound = Elastic property Inertial property

Speed of sound (m/s) Spacing of molecules (nm) 1340 3 Hydrogen Gas (25  C) Carbon Tetrachloride Liquid (25  C) Lead 930 1320 0.4

0.3

Matter: Periodic Table Patterns

What will happen to my voice if I swallow He gas?

A.

B.

The pitch will stay the same.

The pitch will increase.

C.

The pitch will decrease.

Speed of sound = Elastic property Inertial property Speed of sound = frequency times wavelength

Sound Intensities Loudest Saturn V at 50 m Rupture Ear Drum Jet engine at 50 m Threshold of Pain Rock Concert Jackhammer at 1 m Heavy street traffic Conversation at 1 m Classroom Whisper at 1 m Normal breathing Threshold of Hearing 10 -3 10 -5 10 -6 10 -7 10 -10 10 -11 10 -12 W/m 2 10 9 10 8 10 4 10 1 10 0 10 -1 Db 210 200 160 130 120 110 90 70 60 50 20 10 0

Doppler Effect Demonstration

Answer to clicker question:

• slide 9 - B