Tuesday

Hi! I'm Larlyn your scribe for today's class... anyways..

Ms. Kozoriz go over the Vocabulary Review here's the answer....

1. Amplitude

2. Frequency

3. Interference

4. Wavelength

5. Standing Wave

6. Sound Level

7. Open-pipe resonator

8. Octave

9. Resonance

10. Consonance

11. Loudness

12. Dissonance

13. Timbre

14. Doopler Shift

15. Closed-pipe resonator

16. Fundamental

17. Beat

18. Pitch

19. Harmonics

20. Echoes

21. Decibels

And then she said that were having lab tomorrow. She read the yellow booklet we have, starts on page 6-9

Standing Wave Patterns in Longitudinal Waves

In our study of waves in an earlier module, we observed that a standing wave pattern is formed when reflected waves interfere with incidence waves to form a "standing wave" that appears to be standing in place. We learned that the frequency at which the standing wave exists is called the resonant frequency. Each resonance frequency is a whole-number multiple of the lowest resonance frequency called the fundamental frequency.

Sound waves are longitudinal waves, so to understand standing waves in sound let us look again at the Slinky. When the longitudinal waves reflect from a wall, the forward and backwad waves can produce a stading wave. As in a transeverse wave, there are nodes and atinodes. At the nodes the coils of the Slinky do not vibrate at all, that is they do not have any displacement. At the antinodes the coils vibrate with maximum amplitude. This is indicate by the dots with the arrows indicating back and forth movement. At an antinode, the coils have maximum displacement. The vibration occurs along the line of travel of the individual waves. In a standing wave, the molecules and atoms of the medium behave as the dots in the diagram below.

there's the diagram below your booklet.

next she read is about

Standing Waces: Tube open at Both Ends

Musical instruments in the wind family depend on longitudinal standing waves to produce sound. Wind instruments like the trumpet, flute, clarinet, pipe organ, and so are modified columns of air. Sound waves that originate at one end of the tube travel up and down each tube. This is possible because the sound waves reflect from both ends of the tube even though the ends are open. If the frequency of the tuning fork matches one of the natural frquencies of the air column, the downward and upward travelling waves combine to form a standing wave, and the sound of the tuning fork becaomes even louder.

The diagram below the page compare the standing waves in a Slinky on the left with the air pressure patterns on the right. The patterns on the right symbolize the amplitude of the vibrating air molecules at various locations. Where the pattern is widest, the amplitude of the vibration is the greatest. Whenever the pattern is narrow, there is no vibration. In both examples there is a displacement antinode at each end of the tube because air molecules there are free to move. As in the transverse wave the distance between two antinodes is one-half of a wavelength, so the length L of the tube must be an interger number n of half-wavelengths:

Some Formulas and Diagram

Read:

Standing Waves: Tube Open at One End

Measuring the Speed of Sound

Those two are our lab for tomorrow. She also gave us three sheets to work on:

Next Scribe...RAMINA!!!!^_^