Sound test

Hi

First Mrs. K gave us the lab and the test back. After that we had to correct our test and I have the correct answer.

1.V=332m/s+(0.6)(30)
V=332+18
V=350m/s

2.a)10°C b)30°C

v=332m/s+(0.6)(10) v=332m/s+(0.6)(30)
v=338x12.3s v=350x12.3

v=4157.4m/s v=4305m/s

3.a)60db
60-50 10x
50-40 10x

100x

b)10db
40-30 10x
30-20 10x
20-10 10x
1000x

4.compression and rarefaction of air particles

5.no

6.f=30beats/5.0s

f=6Hz

256-6=250Hz

256+6=262Hz

7.The soldiers marching in step has the same frequency as the bridge and they must march out of step.

8.the air column is getting smaller,the (y) is shorter and the frequency increases resulting in a higher pitch

9.)256/2=128Hz

10.

11.leaving your position

12.a)5/4x256=320Hz

b)6/4x256=384Hz

significant figures

S = Significant
N = Not Significant

1.)

A. S, 2

B. S, 1

C. N, 4

D. N, 4

E. S, 2

F. S, 3

G. S, 1

H. N, 4

2.)

A. 2

B. 4

C. INFINITE.

d.2

e.3

F. 3

G. 3

H. 7

I. 4

J. 3

K. 2

L. 3

M. 3

N. 2

O. 5

P. 1

Q. 3

R. 3

S. INFINITE.

t.4

U. 5

V. 3

W. 3

X. 3

Y. 1

Z. 4

Next scribe is Niwatori-san

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.

October 15, 2008

Hi guys! This is Jeamille and I'll be your scribe for today...

First off, Ms. K. gave us back our lab sheet from last week called Sounds and Their Sources and the sheet from yesterday (10 points about the video). After this, we corrected the papers that we were supposed to finish from Thursday. These sheets were called Sound Waves, Unit 1.3 Sound, Concept-Development Practice Page 26-1 and Career of the Month (we just had to read this one).

Here are the corrections:

Concept-Development Practice Page 26-1
1) Longitudinal
2) Pitch
3) 2.5 cm
4) Long
5) a. Behind b. 9 seconds
6) Solids
7) 4 seconds
8) Will not -- Every other push will oppose the motion of the swing
9) 220 Hz
10) Slightly different frequencies
11) 4 Hz
12) 346 m/s

Unit 1.3 Sound
1) 344 m/s
2) 11.75 faster in wood
3) a. 4 083.6 m b. 4 150 m c. 4 305 m d. 4 009.8 m
4) 0.00385 m
5) 640.3 m
6) 13.3 °C
7) a. 347 m/s b. 320 m/s
8) 344.6 m

Sound Waves
1) 1 218 m
2) 8.77 s
3) 1.19 m
4) 642 m
5) v = 330 m/s + (20 C)(.6) = 342 m/s
The echo from 1 wall returns in 0.5 seconds so you take 1/2 the time which is 0.25 s and multiply it by 342 m/s to find the distance to that wall. 342 m/s * .25 s = 85.5 m

Then the time it took for the other echo to return to the person was 0.5 s after he heard the first echo (which was 0.5 s). The total time was 0.5 s + 0.5 s = 1.0 s. You take 1/2 of this time which is 1/2 * 1 s = 0.5 s
The distance to this wall is the speed * time = 342 m/s * 0.5 s = 171 m.
Add the two distances together, 85.5 m + 171 m = 256.5 m.

(this is from Ms. Kozoriz :D)

Before we went on #5 in Sound Waves, Ms. K. gave us a sheet called Consonance and Frequency and showed us how she got the answer for that one.

After correcting these, we did a lab. :) It was pretty easy, I should say. All we needed were straws and scissors. We had to cut the end of the straw creating an almost triangle shape and blow it to produce sound. While observing what happens, we had to answer 2 sheets for this lab and hand it in by the end of class. For those who didn't finish, Ms. K. said it's okay to hand it in tomorrow.

Well that's it for today's class. :))

Next scribe is Charizze a.k.a Chae

Mid-Night Physics....

Yeah, well today... err, I mean yesterday we went over the answers of the lesson 15 vocabulary thingy. Answers below:

1) Amplitude
2) Frequency
3) Interference
4) Wavelength
5) Standing Wave
6) Sound Level
7) Opening-Pipe Resonator
8) Octave
9) Resonance
10) Consonance
11) Loudness
12) Dissonance
13) Timbre
14) Doppler Shift
15) Closed-End Pipe Resonator
16) Fundamental
17) Beat
18) Pitch
19) Harmonics
20) Echoes
21) Decibels

Well, when we finished this we went onto an experiment. We tested the sounds a closed pipe resonator with a tuning fork. To see what sounds it would make when we shifted it up and down a tube full of water. We were testing in which area where you would be able to hear the air compressing and rarefacting. We had 2 kinds of experiments: one of them in cold water and the other in hot water and in all the labs we do theres a lab work sheet that we had to do.

Oh yeah, we read pages 6 - 9 or something like that in the yellow book. The book talks about standing wave patterns in longitudinal waves. I shows where the antinodes and nodes are. We also read about Standing Waves with an open-tube resonator and standing waves with a closed-tube resonator.

Well thats the end of my post the next scribe was total random (not really since i just picked the first one) jeamille. Good luck with that.

SOUND!!!!! and that "Chuck Norris" look-a-like

Heeey! So I figured I should do this first before I lose focus with my other homework (besides I need a small break inbetween English and Bio -_-"). Okay so for those of you who lost track because of the small break inbetween posts that happened recently, this post is for Monday, October 6.

We started the class with Ms.Kozoriz handing back our tests and going over the answers, checking if anyone had any questions about it. For those of you who did well, congratulations and keep it up. For those who didn't do as well, you'll get it next time! (:

I would put up the answers for the test, but it wouldn't make much sense if you did miss today because you won't have your test in front of you. I would suggest getting your test from Ms. K when you can and then just compare your answers with someone in class if you have any questions about it. Between everyone in the class, all the right answers are there. From what I've seen (which is mostly just the people who sit in the front corner with me), a lot of people messed up on the fish question (the one that asked "where is the fish?"), but then there are those people who got it.

After getting our tests back, we read from the bottom of page 4 (Natural Frequencies and Resonance) to the middle of page 6 (Beats and Beat Frequency) in the yellow "Sound" booklet.
I'll quickly go over each concept as best as I can.

Natural Frequencies and Resonance
The natural frequency of an object (example used in the boolet is a pendulum) is the specific frequency at which it freely vibrates. It depends on some sort of length.
ex. shorter pendulum = higher frequency
longer pendulum = lower frequency

Any object that vibrates at it's own natural frequency will do so with the largest possible amplitude it can achieve. This is the frequency where it is easiest for a vibration to happen (also called the resonant frequency). With this, a small, repeated force can create a very large vibration.
ex. (in the booklet) "If a car is stuck in snow, it can be rocked back and forth at the same resonant frequency of the system. This motion builds up the amplitude, helping to get the car stuck in the snow."
If you picture that in your head, it will make resonant frequency and resonance easy to understand.

The Fundamental Frequency
A resonant/natural frequency is the frequency at which a standing wave is able to exist. Some objects, like a tuning fork or a pendulum, have only one resonant frequency. Other objects, like a rope or a stretched spring have many different resonant frequencies. In these cases, all of these resonance frequencies are all a whole-number multiple of the lowest resonant frequency. That frequency is called the fundamental frequency or f0.

The resonant frequencies of the standing waves are also known as harmonics. This is because in music, they harmonize with each other. The fundamental frequency is called the first harmonic. In the fundamental frequency, the distance between the two end points is equal to one half of a wavelength creating only one loop and one antinode.

*Image from :http://www.miqel.com/images_1/jazz_music_heart/harmonics.jpg

Beats and Beat Frequency

This section has a lot to do with constructive and destructive interference. To help you understand this, I drew a diagram (because I couldn't scan the picture xD). Please excuse my horrible paint skills.

So this picture represents the sound waves of two tuning forks hit out of phase (or is it "fase"?). In case you forgot, these were drawn as longitudinal waves because (for me) it's a little easier to see how this works this way. The green boxes represent destructive interference. Here the sound intensity (volume) drops. If the waves that are superimposing have the same amplitude, the sound intensity drops to zero. The purple boxes represent constructive interference. Here, the sound intenisty rises making a louder sound. The periodic variations in the loudness of sound are called beats. They are the result of when sound waves with slightly different frequencies interfere with each other (like in my badly drawn picture). Beat frequency is the number of times loudness rises and falls in one second. To calculate it, you just take the differences of the two sound frequencies.
ex. If sound wave one had a frequency of 440 Hz and wave two had a frequency of 438 Hz, the beat frequency would be 440Hz-438Hz or 2Hz.




So that covers the booklet. Next we worked on a vocabulary review sheet for chapter 15 in the green textbooks in class. For those of you who didn't show up today, here are the questions:

1) The maximum displacement from rest position is the ___of a wave.
2) The number of complete vibrations per second measured at a fixed location is the __ of a wave.
3) The result of superposition of two or more waves is _____.
4) The shortest distance between points where the wave pattern repeats itself is the ____ of the wave.
5) If the period of a wave is equal to the amount of time it takes for the wave to travel to a fixed point and back, the waves reinforce each other and a(n) ____ is produced.
6) Sound pressure is the ____.
7) A resonanting tube that has both ends open is a(n) ______.
8)The difference bewteen two frequencies that have a ratio of 2:1 is a(n)_______.
9) Increasing the amplitude of a vibration by repeatedly applying a small external force at the same natural frequency is _____>
10) A complex wave that has a pleasant sound is a(n) ______.
11) The amplitude of a wave causes the ____ of the sound that is heard.
12) A complex wave that has an unpleasant sound is a(n) _______.
13) Sound quality is ____.
14) The frequency of a sound seems to be higher as it approaches a listener and lower as it moves away from a listener because of the _______.
15) A resonating tube with one end closed is a(n)_____.
16) In a pipe resonator, the lowest resonant frequency is the ______.
17) The oscillation in the amplitude caused when waves of slightly different frequencies are added is a(n) __________.
18) The frequency of a wave causes the ____ of the sound that is heard.
19) In a pipe resonator, multiples of the fundamental frequency are the __________.
20) Reflected sound waves are______.
21) The unit of sound level is the _______.


Word Bank
amplitude, beat, closed-pipe resonator, consonance, decibel, dissonance, Doppler Shift, echoes, frequency, fundamental, harmonics, interference, loudness, octave, open-pipe resonator, pitch, resonance, sound level, standing wave, timbre, wavelength



So after this, we watched more of that guy who looks like Chuck Norris from before (if you don't know who this is, "check your neighbour" xD). This time, he talked about the three concepts that we read about in the yellow booklet. Visual aids always help a lot. Too bad I can't find the whole video so I can post it here. However, I did find these:

Resonance

Interference/beats

And that ends this lengthy post. Sorry if you had to read all of this, but hey, at least you learned something, hopefully. -_-"

Oh right! I got really bored so I had fun choosing the next scribe! The next scribe is:

Congratulations JohnI! You are the next scribe!

DELAYED DEVOTION....To PHYSICS

Delayed Devotion... No I'm not trying to suck up. It just happens to be the title of the song I'm listening to. Google it. ha ha just kidding. I'm a little late with the post, I'm sorry. I wasn't really feeling up to it, even though I said I would do it, mostly because I was watching SNL parody Sarah Palin. ;D

Anyhoo. This scribe post is here to recap what happened since the blog abruptly stopped, so I think that was a Wednesday. On Wednesday, everyone was reviewing for the test the next day using the blue booklet; Waves In Two Dimension. As well as that we were also given review sheets the previous day and reviewed the answers as a class.

The next day was Thursday, and subsequently, we all wrote the test. At the end of class, prior to leaving, we were given the booklet that summarized the next unit, which was SOUND. We're most likely to get thorough on this unit this week.

Finally on Friday, we were given a lab where the objective was to observe the results of making sounds with a ruler on the edge of the table, filling a graduated cylinder with different levels of water and blowing air into it for a sort of windpipe sound and also hitting a "hammer" on a tuning fork. After the class experimented with these items and made different sounds, we were to record our data by answering the questions and hand the paper in.. [but i didn't, tee hee. I will.. I'm just perfecting the paper.]

Then we also had to grab a worksheet CHAPTER 15 Vocab review and fill in the blanks in which we are probably going to go over tomorrow. That's all for today folks...

OH YEAH... next scribe....jaaaayp :D