October 16, 2008

Hello. I didn't know we had to do this again but oh wells. Ok so what happen in class today was when we walked in, Ms. Kozoriz had the smart board up and had the VIRTUAL KEYBOARD.

If you like to see the keyboard go to this website: http://www.bgfl.org/bgfl/custom/resources_ftp/client_ftp/ks2/music/piano/index.htm

Ms. Kozoriz taught use how to measure Decibels.
If 0 dB -> 10 dB it equals 10x the intensities.
If 10 dB -> 20 dB it equals 10x the intensities.
If 0 dB -> 20 dB it then equals to 100x.
The reason why it goes to a 100x is because it first goes from 0 dB -> 10 dB which is 10x, then the 10 dB-> 20 dB which is another 10x. So its (10x)(10x) = 100x


Next, did the Problem in the yellow booklet on page 27, as a class.
(I didn't get to copy all questions so I asked Nelsa for some of them. Thank you!)

ANSWERS

1. The larger the ears, the more sound energy is received.

2. 1000 (each level is multiplied by 10)

3. The whistle is an ultra-sound wave, which is a higher frequency than normal to human's hearing.

4.
a) Amplitude

b) Frequency

5. The army made sounds from the cannon barrage, that were making vibrations. And the vibration came in contact with the snow and caused the avalanche.

6. 40 dB -> 80 dB = 10 000 or 10^4
Steps

1. 40 dB -> 50 dB = 10x
2. 50 dB -> 60 dB = 10x
3. 60 dB -> 70 dB = 10x
4. 70 dB -> 80 dB = 10x

So it then becomes: (10)(10)(10)(10) = 10 000 or 10^4

7. Media

11.

a) 5 seconds

b) f = 1/T = 1/5 = 0.2 Hz

17. The wavelength increases when it travels into water because it's moving faster.

18. The pitch would be lower due to the Doppler Effect because the jet is going away from the observer.

19. A higher frequency.

21.

a) The person holding the radio, it would not change the frequency or the pitch.

b) The person left behind on the platform the frequency still doesn't change, but the pitch would be lower, because it's going away from the person.

c) The person on the rubber raft the frequency still doesn't change, but the pitch would be higher, because it's going towards the person.

22. G - B - D

G = 384 Hz

(5/4)(384Hz) = 480 Hz

26. C = 256 Hz

So, 256 Hz + 256 Hz = 512 Hz - first octave

then 512 Hz + 512 Hz = 1024 Hz - second octave

THE END

Next Ms.Kozoriz handed us back our 10 - interesting points from the video we saw yesterday, or two days ago. And she handed us a 19 Transparency Worksheet: Decibel Scale. She gave us some time and we corrected it.

ANSWERS

1. 90 dB

2. Soft Whisper - Bedroom at night

3. Average Classroom - Inside compact car

4. A jet airplane taking off

5. Soft Whisper

6. Average Classroom

7. Heavy Truck

8. Jet airplane taking off

9. Soft Whisper

10. 120 -2x10^1 = 20 N/m^2

THE END

So that is what we did in class, and pretty much yeah. I pick Lorenz to do the next scribe. Oh! WE HAVE TEST TOMORROW!!! STUDY STUDY STUDY!!!!