September 16, 2008

hey guys...i guess its finally the time for the hero to emerge in this blog to write the post...anyways, this is what we did in class:



First, class started a little late due to a lock down...i have an idea of what happened, but I'm not sure if it's true or if I'm allowed to say what i think happened on this post. Once class started, we corrected questions 7-14 in the blue booklet, which were assigned...at an earlier time...There was a lot of drawing involved, so if you want to check your answers, you should go check with a fellow classmate in order to ensure success in the test tomorrow, because I'm not so good at paint. We also handed in the 25-3 sheet (the sheet where we needed to draw constructive and destructive interferences between 2 waves and the ultimate wave on the back). We also went over the wave characteristics worksheet that i believe was assigned yesterday. Seeing as there are no drawings involved, i shall post the answers.



1) a) 0.0165 m b) 16.5 m

2) 2.9 m

3) 922000 Hz

4) 12 m/s

5) a) 8 s b) 0.125 Hz c) 16 cm d) 2 cm/s



If you're having problems with the...problems i suggest you go ask a friend for help before the test tomorrow.



Nearing the end of class, we were given another worksheet. This worksheet was titled: 18 transparency worksheet - wave properties. In this worksheet, we basically learned the properties of transverse and longitudinal waves as well as compare the two with each other. I was zoning out while we were correcting the answers, but i think i was able to get some correct. I believe the answers go as follows:



1) transverse and longitudinal/compressional waves

2) longitudinal/compressional waves

3) transverse wave

4) they are displaced parallel to the direction

5) transverse wave

6) compression can be compare to a crest, and rarefaction can be compared to a trough

7) transverse - crest to crest / trough to trough

longitudinal - compression to compression / rarefaction to rarefaction

8) the wavelengths are equal

9) the size of the compression or rarefaction

10) longitudinal/compressional wave



If some of the answers i posted up were wrong, then i apologize.



Finally, at the end of class, we did a little review of what will supposedly be on the test. I'm not sure if i caught everything, but some of the things i heard include waves (duh), movement of waves through different mediums, partial reflection/transmission, nodes (parts of a wave that doesn't move), and anti nodes (the high and low points of a wave). Just in case, though, i suggest you study everything we learned up until now for the test tomorrow.



This concludes my summary of the class for today, if you have any questions please do no hesitate to ask the teacher as well as some of my friends (including Karen, PJ, Mary, Pacifico, and maybe even Roger). You might as well ask everyone in our class. Well, that's all for now.



Bye Folks!

BTW the next scribe will be Niwatori-san!

15 September 2008

Hi .. haha
So, my name is Karen, and I am your scribe for today. . (thanks Roger -_-)

Today, we went over the Chapter 14 Study Guide. We corrected, and went over: Types of Waves, The Measures of a Wave: Frequency, Wavelength, and Velocity, Amplitude of a Wave, Waves at Boundaries Between Media, Superposition of Waves, and Standing Waves. We didn't go through the last three topics because Ms. Kozoriz said that it will be in our next lesson/unit or yeah.

---------------

Just in case you missed some, here are the answers
TYPES OF WAVES
mechanical
material
electromagnetic
no
particles
matter
three
perpendicular
motion
parallel
motion
surface
parallel
perpendicular
single
continuous
vibrating
harmonic

THE MEASURES OF A WAVE: FREQUENCY, WAVELENGTH, AND VELOCITY
shortest
motion
vibrations
second
Hertz
Hz
Hertz
f= 1/T
T
f
wavelength
λ
high
low
v= fλ or v= λ/T

AMPLITUDE OF A WAVE
maximum
equilibrium
more
energy

WAVES AT BOUNDARIES BETWEEN MEDIA
amplitude
frequency
properties
equal to
equal to
incident
transmitted
energy
reflected
most
little
inverted
erect
frequency
speed
wavelength

SUPERPOSITION OF WAVES
independently
displacement
sum
displacement
superposition
the same
larger
shape
size
opposite
zero
destructive interference

STANDING WAVES
undisturbed
destructive
displacement
constructive
standing
stationary
standing still


----------


Ms. Kozoriz also went over the difference between Low Frequency Waves and High Frequency Waves and she also talked about the difference between High Amplitude and Low Amplitude. I think she's hinting that they're going to be on the test. *wink, wink, nudge, nudge* yeah..

So, the difference between High Frequency Waves and Low Frequency Waves...



High Frequency Waves have more pulses per second, and they also have shorter wave lengths than Low Frequency Waves.





HIGH AMPLITUDE vs. LOW AMPLITUDE


Well the difference is obvious. High Amplitude Waves, has higher amplitude and Low Amplitude Waves has lower amplitude. Easy right? Ms. K also pointed out that High Amplitude produces a louder sound.



WAVES AT BOUNDARIES BETWEEN MEDIA








I'm not sure if the animation is working, but heres the link to the site where i found it. The site also explains what happen to the pulse as it moves from a less dense medium to a more dense medium.

CLICK (:



SUPERPOSITION OF WAVES
Well, I found videos which shows what happens during Destructive Interference and Constructive Interference





DESTRUCTIVE INTERFERENCE
- This occurs when the wave displacements are in opposite directions.
- The displacement produced when the two pulses meet is zero.





CONSTRUCTIVE INTERFERENCE
- Occurs when wave displacements are in the same direction.
- Results in a wave with a larger displacement. (sum of the displacements that would've been produced by each wave independently)



STANDING WAVES





Yeah.. I'm not done yet.
According to the study guide, "When two waves meet, a point in the medium that is always undisturbed by the wave is called a node" Nodes are produced by destructive interference.
An antinode on the other hand is produced by constructive interference, and again according to the study guide ;) "it is the point in the medium where there is the greatest displacement"
In a standing wave, the nodes and antinodes are stationary, and the wave appears to be standing still.







So, after we finished correcting the study guide, Ms. K gave us two worksheets
Wave Characteristics and Wave Superposition.
Wave Superposition is to be handed in tomorrow. And we're also going to go over questions 7-13 from the blue booklet.

TEST ON WEDNESDAY ! D:

yuuuhp. sorry about the long, boring post.

Next scribe is..
Mr. Jonathan Paguia (:

Friday, September 12, 2008

Hey everyone, sorry for the late post i have been very busy. Anyways, heres an overview of class on friday.

at the beginning of class we started off listening to a song about wave motion called, Wave motion. I guess it's just a different way to understand the concept. Personally, putting physics into song just doesnt work for me. well after that, we went over questions 1 to 6 in the blue booklet, waves in one dimension. After going over the questions, Mrs. Kozoriz gave time to anyone that did not finish the study guide about wave properties given the day before. She also assigned the rest of the questions (questions 7 to 14) in the blue booklet which is due on Monday.

ALSO, test on wednesday!! i think..
and the NEXT BLOGGER IS KAREN!

Sept.11/08

Good morning guys! sorry about the late blog, there was a little confusion on to who was the next scribe. i'll try to condense everything, so there isn't much to read over. bare with me and my lack of spelling/grammar. either way, here it is!

during the previous class, we had a substitute who went by the name mrs.hodgson. she had assigned us two sheets,"chapter 14.1-2 study guide", related to pages 288-301 in the text book. The sheets were basically fill in the blanks and were fairly simple. (if you read closely to the text from the text book). It had topics such as Types of Waves, The Measures of a Wave, Amplitude of a Wave, Wave interference, superposition of Waves. Standing Waves, Reflection of Waves, Refraction of Waves, and Diffraction of Interference of Waves.

The substitute was hinting at a quiz or test, because of the title "study guide". i'm not too sure if this coming test/quiz is ture or not, but its better to have finished the sheets. right?

i'll add more info on the topics after school, because i need to leave for cross country practice. (can I do that? LOL sorry!)


Next scribe is ROGER, bye bye!
Mary (:

Scribe Wednesday, September 10th

hey gangsta's this is kale doin' his first scribe

well in class today we started off by taking attendance then shortly after we corrected the 4 worksheets that were assigned on monday, i hope everyone did well, i myself got almost everything correct.

anywho, after that we were assigned to read parts D, E and F (pages 5,6 and 7) in our blue note booklet, then do questions 1-6 on page 12. I will summarize parts D, E and F for you guys.

Part D: Reflection
This part explained how when a pulse hits a wall, it comes back the other way. Here is a simple diagram explaining it.



















(Okay dude, underline went on and i dont know how to take it off, so yeah)
anyways it's a pretty easy concept to grasp, you just gotta know that when the pulse hits the wall it exerts a force upward on the support, which then exerts and equeal (but opposite) force down. This force makes the inverted pulese.

When There is no barrier, the rope's pulse will reflect on the same side, like so.



nice, its not underlined anymore
anyways the rope is free, so when the pulse reaches the end the particles exert an upward force, sendin' the pulse back as an imcoming pulse.

E: Wave Transmission in Two Media
The speed is constant when a pulse travels through a medium, but if two different mediums were connected and had different densities, the speed would change abruptly. Frequency will not change as it is a constant. The equation v=fλ shows how to calculate this change.
An example would be connecting a light rope to heavy rope, the wavelength and the speed would decrease, and vica versa =]

F: Wave Transmission and Partial Reflection in Two Media
on the connection between to media, some reflection may occur, this is called partial reflection. Some energy is reflected back to the first medium, and some is transfered to the next. There is no change in speed, wavelength and frequency in the reflected pulse.


here is a little example i cooked up, it just shows the inverse pulse reflection

When a wave goes from a big rope to little one, there is no inversion, but still some reflection.
The littler rope acts like a free end, but its not quite.




When moving from a large to small rope the pulse moves faster and has a greater wavelength, but isnt inverted

there it is, my first post (try to ignore some typos and/or grammatical errors

September 9, 2008

Hello everybody! It's my turn to scribe so here is what we did today!

In today's class we did a lab called, "Waves on a Snakey." The purpose of this lab was to investigate properties of waves using a snakey (slinky) as a model. After Mrs. Kozoriz explained what we were going to do, she distributed the materials we needed and we broke into groups and got started. The entire class was spent with everyone crouching on the floor and watching in amazement as two people stretched the slinky, and by making quick sideways snaps with our wrist, we created the waves that traveled down, hit the other side, and reflected back. While doing so we had to observe the waves and think about what was happening to the amplitude and the speed of it as it traveled. My group didn't have much trouble, although we debated whether or not the pulse did in fact bounce off each other or pass through. We did ponder on what the meter stick and stop watch was used for, but other than that everything was fine.

Along with this lab we were given a worksheet that should be completed and handed in TOMORROW! And.. I think thats it. I don't know what else to put so I'll end it here.

The next scribe was picked by random so congratulations 'kaleiscool'! You're next! Have fun!

September 8, 2008

-Piisu~!
...
...
LOL

Anyways...

Deadline:
Job ad that needs Physics or something like that

Today, we started the unit about Waves by learning about Waves in One Dimension.

Vocabulary:

• continuous/periodic wave: a wave that is made by a disturbance that is moving back and forth periodically, i.e. the source is oscillating or vibrating.
• transverse wave: the particles of the wave vibrate up and down while the direction of motion is to the left or right.
• crest: high point on a wave.
• trough: low point on a wave.
• amplitude (A): maximum height of a crest or depth of a through from the equilibrium level (rest position).
• cycle: one complete oscillation (one complete up and down movement in the case of a transverse wave).
  
• wavelength (λ): horizontal length of one cycle of the wave; can be described as the horizontal distance between two successive crest/through or any successive equivalent points on the wave.
  
• longitudinal wave: the particles of the wave vibrate the same direction as the motion of the wave.
• frequency (f): number of cycles that pass a given point per unit of time; commonly measured in cycles per second or hertz (Hz).
• period (T): time elapsed between two successive crests/troughs/equivalent points passing by the same point in space.
• wave velocity (v): velocity at which the wave moves.
  
• longitudinal wave: the particles of the wave goes the same direction as the motion of the wave.
  
• compression: areas in a longitudinal wave that are momentarily close together.
• rarefactions or expansions: areas also in a longitudinal wave that are momentarily far apart.

Formulas to remember:
T = 1/ f
v = λ/T
v = f * λ
f = 1/T

Assignment:
Periodic and Frequency Problems Sheet
Vibrations and Waves Sheet
Characteristics of Waves Sheet
ALL DUE WEDNESDAY

Well... That's it...
Next scribe is arielle!