Chae: October 16, 2008 (:

Hi there! This is Charizze, your scribe for today ^-^

First of all, I would like to remind all of you guys that we have a test tomorrow [Friday, October 17] about the Sound Unit.

Well, I was a tad late for class today but I didn't miss a lot. They already started answering the Problems in the Sound Unit Booklet when I arrived. I only missed questions number 1 & 2, but I got the answers from others. I was surprised because I thought we were to answer the problems for homework. But Ms. Kozoriz just went over it as a review for tomorrow's test.

Anyway, here are the answers:
1.) Larger ear - easier to pick up sound (low frequency)
2.) 10 * 10 * 10 = 1 000 dB
3.) It can hear higher intensity sounds
4a.) Amplitude
4b.) Frequency
5.) Vibrating of the sound waves carry energy
6.) 16 times louder or 10 000 the intensity
7.) A medium -> air, water, wood, etc.
8a.) Intensity - quantitive way to measure sound
Loudness - objective / point of vew
8b.) Frequency - exact value
Pitch - can vary
Skipped #9
10a.) 529Hz - 524Hz = 5 Hz
10b.) t = 1/f => 1/5 = 0.2 s
11a.) 5 s
11b.) f = 1/t => 1/5 = 0.2 Hz
Skipped #12 & 13
14.) 440 + 5 = 445
436 + 9 = 445
Skipped #15
16.) wavelength = v/f => 331m/s / 261.6 Hz = 1.27m
length = wavelength/4 => 1.27m / 4 = 0.316m
17.) The wavelength of sound will increase.
18.) Lower pitch
19.) Higher
20a.) v = 331m/s + (23) (0.6) = 345m/s
20b.) d = vt => (345m/s) (10*10^-3 s) = 3.45m
21a.) None
21b.) Lower frequency
21c.) Higher pitch
22.) 4:5:6 => G B D
G = 384 Hz
B = ? => 5/4 * 384 Hz = 480 Hz
Skipped #23, 24 & 25
26.) c = 256 Hz
c 1 = 256 + 256 = 512 Hz
c 2 = 512 + 512 = 1024 Hz
Skipped #27 & 28

Those that were unanswered (skipped) are not going to be on the test.


We were also given a worksheet to answer based on the scale on the overhead.

Here are the answers for the Decibel Scale Worksheet:
1. 90 dB
2. Soft whisper(70 dB) and Bedroom at night (10 dB)
3. Average Classroom (50 dB) and Inside a compact car (70 dB)
4. Jet airplane (120 dB)
5. Soft whisper (10 dB)
6. Average classroom (50 dB)
7. Heavy truck (90 dB)
8. Jet airplane (120 dB)
9. 2*10^-5 = 20 dB -> Soft whisper
10. 2*10^-1=20N/m^2 => 120 dB

I'm sorry if some of the answers here didn't seem right. I suggest you ask our fellow classmates for more information.

That's what we practically did for the class. We just prepared for tomorrow's test. Just to make sure, study everything that we did for the Sound Unit.

Good luck on the test you guys! :)

Next scribe is.. well there's one more left and it is abbas.