October 14th

In today's class, we did three questions from our booklet which was questions 21(a,b,c) 22 and 26.
We also went over on what to review on the upcoming test. The review included pages from the booklet or the "summary" near the end if a condensed version of the whole thing is wanted instead(not including the page 14 sound perception/sound wave characteristics guide.

October 13, 2010

We made a straw oboe by trimming the end of a drinking straw and placed the flattened double reed part of the straw oboe between our lips to play it. We learned that the reed vibrates to make sounds. We also did some problems from the sound unit booklet.

Concept-Development Practice Page 26-1

Concept-Development Practice Page 26-1

Sound:

1) Two major classes of waves are longitudinal and transverse. Sound waves are:

Answer: Longitudinal

2) The frequency of a sound signal refers to how frequently the vibrations occur. A high-frequency sound is heard at a high:

Answer: Pitch

3) The sketch questions answer would be: 2.5

4) Compared to the wavelengths of high-pitched sounds, the wavelengths of low-pitched sounds are:

Answer: Long

5) Suppose you set your watch by the sound of the noon whistle from a factory 3 km away:

a. Compared to the correct time, your watch will be:

Answer: behind

b. It will differ from the correct time by:

Answer: 9 seconds

6) Sound waves travel fastest in:

Answer: solids

7) If the child’s natural frequency of swinging is once each 4 seconds, for maximum amplitude the man should push at a rate of once each:

Answer: 4 seconds

8) If the man is Question 7 pushes in the same direction twice as often, his pushes:

Answer: will not

Be effective because

Every other push will oppose the motion of the swing

9) The frequency of the tuning fort is 440 hertz. It will NOT be forced into vibration by a sound of:

Answer: 220 hertz

10) Beats are the result of the alternate cancellation and reinforcement of two sound waves of:

Answer: slightly different frequencies

11) Two notes with frequencies of 66 and 70 Hz are wounded together. The resulting beat frequency is:

Answer: 4 hertz

12) The accepted value for the speed of sound in air is 332m/s at 0⁰C. The speed of sound in air increases 0.6m/s for each Celsius degree above zero. Compute the speed of sound at temperature of room you are now in:

Answer: 332m/s+ (0.6) (20⁰C)

=344m/s @20⁰C

Sound Unit

Today we began to study "Sound" for our next lesson. To start this lesson off we did a lab. Using a ruler, tuning fork, cylinder and water, we learned how to create sounds with them and how to vary their pitch. The material covered was somewhat new to me and from what we learned so far I don't think it's a hard concept to understand.