Investigation 10.2

  To start the class off, we went over questions from the text that were assigned yesterday. We reviewed the universal wave formula which is v=fλ and can be manipulated to apply it to what the question's asking for. A good way to use this is the universal wave triangle. Cover up which ever variable you are needing to find out and what's left should give you the proper formula. For example, if you need to figure out the frequency, cover the f with your finger and what's left is v over λ. So your formula would now be, f= v/λ.

  After that, we looked at Investigation 10.2: Transmission and Reflection of a One-Dimensional Transverse Wave. The problem is, how is a transverse wave in a coiled spring transmitted and reflected? We got into groups and were assigned to experiment and examine results when we followed the procedure done with a slinky. After observing results, we wrote down the information we had to best answer the question in the procedure. We were also assigned questions 1-6 although we did not have sufficient time to get through all the assigned material.

The next blog post will be submitted by Mackenzie.

The Transmission and Reflection of Waves

To begin class we were given time to finish up any work left on our slinky lab called Transmission and Reflection of Transverse Waves. Many slinkies were tangled resulting in Mr. Banow getting upset. By the time we got through this lab we had just enough time to write some lovely notes.

According to Mr. Banow, when a wave hits a fixed end it reflects inverted (on the opposite side). The properties of the medium also affect the speed of the wave, or velocity. A good example of this is: the speed of water waves depends on the depth of the water.

In some cases the medium is constant. When this happens waves with a high frequency will result in a short wavelength and waves with a low frequency will result in a long wavelength.

From our slinkies we learned that the wave never really slows down, just dies out. In other words, amplitude does not affect a wave's speed. But, the more energy there is the longer the amplitude is. The reason for energy being lost is less friction.

http://www.youtube.com/watch?v=ysSoiA6luQ



The next blog will be written by the winner of a rock paper scissors tournament between Taylor, Cody, and Rachel. :)

Universal Wave

we started off class by talking about a universal wave. Universal wave equation- there is a relationship among speed,frequency and wave length that build true for all waves.

wavelength is the distance a wave travels in the time required for a complete oscillation (crest to crest). the time for one oscillation is called the period.

we know that :

an example would be:
the wavelength of a water wave is .80 m. if the frequency of the wave is 2.5 Hz(cycles per second). What is the velocity of the wave.
V= f λ

V=(2.5 Hz)(0.80)

v= .20 m/s

to end the class he assigned page 211 questions practice #1 and all section 6.3 questions for today in our physics 20 books

the next blog post will be written by cody :)

Sources of Errors

We began class by discussing last Friday, in which we were assigned to do a project titled "Analyzing the Motion of a Pendulum." For this assignment we had to identify what the relationship was between the length and the frequency of a simple pendulum using an apparatus, a stop watch, and a protractor.

Before we were allowed time to finish the assignment, we discussed sources of errors and why they are important. A measurement is only as accurate as the error involved in the measuring process. So the uncertainty of a measurement is as important as the measurement itself.

There are various possible factors that might affect the accuracy of an experiment.

When we label an experiment on a graph (like shown on the left) we circle the dots on that said graph to show that the measurement is not completely exact and the dot could be practically anywhere in that circled area.

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After that discussion we were left the rest of the class to work on our assignment we were assigned on Friday using the things we were recently taught. Class came to an end and the assignment was said to be due on Wednesday.

The next blog post is going to be written by Evan.

Our First Lab:Analizing the Motion of a Pendulum

In Fridays class we went over the work sheet we had done in the previous class, correcting an elements of physics work sheet. That was filled with fill in the blank and true and false questions, based on a video we had watched.

Then we got a hand out with the list of labs we would be doning in Physics 20. We also learned how to properly write out the labs by titling the title, problem, materials, proccedure, data and observatoin, and ending off with a conclusion.

We started our first lab, Analizing the motion of a Pedulum. During this procedure we used an apparatus, stopwatch, protractor, and various size's of weights. In this lab we had to determine the lenght of time in seconds, it is required to take in 10 cycles. You would then start with the length of string at 100cm, and then decrease the length by 20cm each time at a 20 degree angle. This will help determine the frequency of the pendulum for each length. Then you are asked to create a chart and answer the following questions of What happens to the frequency of a pendulum as its length increase? What happens to the period of a pendulum as its length increase?

Then you had to repeat one of the previous procedures, by useing the identical length in the first observation, but change the degree of 20 to an angle of 10 degrees. Then record the frequency and compare.

The next step is to repeat one of the procedures you have already done, with a smaller size of weight, and compare the frequencys that you have already obtained by the previous recorded data. Be sure sure to use the 20 degrees and not the 10 degree angle, then record and compare.

We ended off the class by putting away all of our materials we used, and im pretty sure we will be given more class time to work on this lab on monday.

The next person to write for the blog is Summer Harris. :)

WAVES: SOUND AND ELECTROMAGNETISM

To begin the class we first worked on the assignment we were given the previous day in our text books, for 15 minutes. This assignment allowed us to practice the material we learnt Wednesday about: transverse and mechanical waves also leading to the mathematics of how to find the frequency and period of the waves.( The frequency would be measured in Hertz (Hz) and the period would be measured in seconds)

After working on the assignment from last day, we were given a booklet and worked on the Pre-Test on the first page for 15 minutes before watching a 20 minute video about waves involving sound and electromagnetism, the Test consisted of 10 true and false questions, on the back of the Pre-Test were definitions we also studied before watching the video.The Pre-Test was assigned to see how much we knew about waves and its sound and electromagnetism already.

There was a lot of new information in the video about waves. we learned a lot of answers to interesting questions. We learned about how sound and light waves travel. The energy of sound, explosions and earthquakes are all transported by longitudinal waves and energy of visible light is transported by electromagnetic waves.

We learned about an effect called "the Doppler Effect" which was explained in the video by a car honking its horn constantly when driving by while the listener hears the horn in different pitches as it drives by. The pitch of the sound is higher as the source approaches the listener and is lower when t retreats away from the listener.

Sound also travels in different speeds in different environments. Sound waves travel faster in a environment like water then in the air. This happens because the sound molecules are closer together making it easier to vibrate each molecule to make a sound.

We also learned about an important subatomic particle called photons, which are a particles of energy and matter propagated by electromagnetic waves. Waves can also change directions when they bounce off of a barrier, these kind of waves are called reflective waves, like echos and mirrors.

After the video we filled in the rest of the booklet to the best of our abilities. Whatever was not done we had to complete for homework. most of the questions were fill in the blank and at the bottom we had to answer 3 questions in a few sentences in our own words.

This class was very productive and I'm sure we all learned quiet a lot about waves and how they travel.

The next writer for our class blog will be Sarah Frey

Waves: Not Just the Ocean Variety

In class today, we started our Waves Unit by learning definitions that concern waves.

Wave: a transfer of energy in the form of a disturbance

Mechanical Wave: A wave that requires a medium to pass through (i.e. sound and water waves). For example, there is no sound in space because there is no medium in space.

Electromagnetic Wave: A wave that does not need a medium (i.e. light, radio waves). For example, light needs to be an electromagnetic wave because, otherwise, how does the light from the sun get to the earth?

Matter Wave: A wave concerning electrons and other particles. These particles' behaviours can be predicted because they move in waves.

We also learned about two different kinds of waves.

Transverse Wave: A wave that vibrates perpendicular to the direction of the rest axis.

My favourite example of a transverse wave would be, of course, a guitar string. The following video demonstrates amplitude, wavelength, and the equilibrium position. It also includes some guitar licks, just so you know that I know my stuff.

The example of amplitude is a little hard to see, so before you watch the video, I will explain it. I first pluck one of the strings lightly, causing a decreased amplitude. After, I pluck the string harder and the amplitude increases.




Longitudinal Wave: A wave that vibrates parallel to the direction of the rest axis. An example of this wave would be a spring compressing, like in a pogo stick.

In this wave, compression is the part that is compressed and the rarefaction is the part that is not compressed.


Even though this stuff with waves is very interesting, the most interesting thing that we have learned today was that, no matter how tangled a slinky gets, it can be untangled.

Review

Today in class we began with a review on how to add, subtract, multiply and divide with significant digits. Then we got a sheet to work on for practice with working with significant digits. On the back side we worked on formula manipulation and working with word problems.

Ex: light can travel at $3.00 x 10^8 m/s$. How long long will it take for the light to go to the moon?
v = 300 000 000
d = 384 000 000
t = ?

$t = d/v$
$t = 384 000 000/300 000 000$
t = 1.28 sec.

Near the end of class we got our exam review. the person who will be writing Sept. 16 blog will be Michelle.

Wednesday, September 14, 2011

Today we began class by reviewing the Significant Digits Rules, then learnt how to add, subtract, multiply and divide the Sig Digs.

Adding and Subtracting

The answer must have as few decimal places as the numbers being added or subtracted.

Ex. 6.234+2.12+3.4=11.8

You have to be sure to round the answer to the least decimal place.

The same rule applys for subtracting Significiant Digits.

Multiplying and Dividing

1. Note the measurement or factor with the least Significant Digits.

2. Calculate as normal.

3. Round the final answer to the number of digits.

Ex. (3.22m)x(2.1m)=6.762 correctly written as 6.8m^2

Following that we got a review sheet for the test on Friday and just worked on that until the bell.

The person responsible for Thursday, September 15 blog post will be Jessica Hilgers.

Tuesday September 13, 2011

We began class with a review on multpilying and dividing with Scientific Notation. This was a review from what we learned with the substitute on Friday. One of the examples are as follows:
$(1.2x10^6m)(2.5x10^4m)=3x10^1^0m^2$

Following that we continued notes we started on Friday on Parallax, Precision, Accuracy, Significant Digits, and Rules for Significant Digits.

Parallax - the shift in position when viewing objects at different angles. Measurements musst be made at eye level
Precision - The degree of exactness that measurement can be reproduced. E.x: 5.14 m is more precise than 5.1 m.
Accuracy - To the extent that a measurement agrees or compares with an accept value or standard.
Significant Digits - When measuring, the precision and number of digits is limited. Significant Digits consist of the all the digits known with a certainty plus the first digit that is uncertain.
Rules for Significant Digits - All non-zero digits are significant
-Zeros between nonzero digits are significant
-All zeros to the right of a decimal are significant
-Zeros only used for spacing the decimal are not significant

All of these definitions are different methods for using, measuring, adding, subtracting etc. with numbers.
The person responsible for Wednesday, September 14th's blog post will be Brooke Ries. :):)

Trial Post

Hello class. This is a test.