The Nature of light: Part 2 The Wave and Particle models of Light

Hi! Yup..I'm the scribe for today..



For today's class we went over the question in the booklet (question 13-15) I'm really sorry if i can't post the answer to that question. Anyways, after that Ms. Kozoriz gave us a work sheet. the work sheet is below:























and don't forget to read page 21-26 on your booklet "Nature of Light PART2" I think lol..^_^ anyways... that's it for now..next scribe is KIM.!..!...^_^

November the 5th

Hello classmates=] So yes, today in class we continued the The Nature of Light: Part Two topic by discussing Young's Experiment. But before we go there, we also corrected yesterday's homework questions (9-12 from the question booklet), so here are the answers to those questions...


9. You were asked to draw the wavelets at each of the places where the light rays intersect with the wave CD, so the blue curves that don't look very blue after upload are those wavelets...

10. In your diagram include...
a) the wave ray indicating the direction ofmotion of the reflected wavelet
b) a possible location of the wavefront
c) the correct location of the wavelet in relation to the wavefront
d) the angle of reflection

11. a) When waves move from deep water to shallow water, the wavelength of the wave would become smaller and the speed would decrease.
b) According to the wave theory, the speed of light is slower in an optically denser medium while the corpuscular theory states the opposite - speed is faster in the denser medium.

12. If we wanted to observe the diffraction of light as it passes through an opening, the opening should either be smaller or the same size as the wavelength of the lights used in order to observe the effect.


And that was it for the previous homework questions. Next, we read about and discussed Young's Experiment which can be found on pages 17-20 in the green booklet, so make sure you read about that. Part of what we discussed in class included the interference patterns produced by light, and it's pretty interesting, especially as explained by this video which we also watched in class... http://www.youtube.com/watch?v=DfPeprQ7oGc. And another site that further discusses light interference patterns: http://www.colorado.edu/physics/2000/schroedinger/two-slit2.html. Haha, yupp=]]



For homework tonight, just make sure you finish questions 13-15 in that same question booklet. Well that's basically all for today. I'm gonna wrap it up here... tomorrow's scribe will be Larlyn. Is that okay? Okaayy... See yah tomorrow guysss.

A Beautiful Day To Blog!

Hola, Nicole here!
Such a beautiful day out... too bad it isn't going to last!

Alrighty, on with the blogging!
Today we were reminded that "Contributions to the Determination of the Speed of Light" is due tomorrow if you didn't hand it in today.

We also were given "The Nature of Light: Part 2 - The Wave and Particle Models of Light Problems" booklet and were told to do questions 1, 3, 4, 5, 6, 7, and 8.
We then corrected them, and here they are:

1. Question
When a "particle" such as a steel ball strikes a hard surface, its speed is usually reduced. If the speed of light were reduced how would the light appear to be different after the reflection as compared to the incoming light beam? (Need to use knowledge of how the speed of light, the wavelength of light, and the frequency are related from your work on waves.)

Answer
Simply the wavelength would change with the speed, since the frequency is a fixed number. The colours would change, and I thought of ROYGBIV. Red being the slowest, and violet being fastest.


3. Question
From the brief descriptions given above of Planck's quantum hypothesis, how does it compare with Newton's corpuscular theory?

Answer
In Planck's theory, energy came in small packets called quanta, which is somewhat similar to particles.


4. Question
We know now that Newton's corpuscular theory had limitations and that light really does not consist of particles. What can we learn about placing too great a belief in a theory and the kind of evidence needed to support the theory?

Answer
We learned that you need a lot of evidence, pure evidence that came from experimentation to support theories such as this.


5. Question
Galileo attempted to measure the speed of light using lanterns on two hilltops. Explain why this technique might have worked if he was attempting to find the speed of sound, but now the speed of light.

Answer
Simply sound is so much more easier to measure since it is much much slower then light.


6. Question
What technique allowed Fizeau to measure time accurately enough to determine the speed of light much better than Galileo?

Answer
Click here for a very good description of what Fizeau did.


7. Question
What was it about Michelson's technique that allowed him to measure the speed of light so accurately?

Answer
Click here to see what Ms K showed us describing Michelson's technique.
The large distance and speed of rotation is what made this accurate.


8. Question
After doing his experiments on two mountains, Michelson did another series of experiments in a long evacuated tube. What improvements did this new method have?

Answer
Since the tube was 1.6kms long, this eliminated haze and air density which can alter results.


After that, we were given another "Chart for Evaluating the Models of Light" and are told to do it on the Wave Model. I believe its due tomorrow.

Anyways, that is it :) Archimedes is to scribe for tomorrow!

October 30th and 31st

Hey everybody it's Alex :). Sorry about Thursday-my bad! To make up for it I'm going to do both Thursday the 30th scribe and Friday the 31st scribe.

Thursday

On Thursday we corrected the test. In case you missed that I'll go over it.

1) a) Numeric
b) Symbolic
c) Visual
d) Graphical

2) e
j
a
h
i
f
b
d
g
c

3) This would be an observation because you're realizing and observing that when you tilt the box something is rolling around inside it.

4) Yes, this could be an example of a scientific model because stating that there is a marble in the box gives us a mental picture to work with and allows us to picture a object rolling around in the box more accurately.

5) The type of evidential arguments that would support this statement are; coke has the best flavour, is the most accessible soft drink (sold everywhere), everyone drinks it and it has the best price.

6) a) 2
b) 4
c) 1
d) 4
e) 3

7) a) 25.6cm
b) 4.5 x 10 to the -4

8) For question 8 you had to make a graph. Make sure you plotted the points correctly, had a title for your graph and had Time (s) on your x-axis and Position (m) on your y-axis.
b) Linear
c) Position varies directly with time.
d) To calculate the slope you must choose two points on your graph that lie where the vertical and horizontal lines intersect. Then plug your two points into this equation:
Y2-Y1/X2-X1
Then make sure that you put the answer in decimal form not fractional form.

On Thursday we also did a lab. This lab was based on Newton's particle model for the refraction of light. We rolled a ball down a ramp and measured the refraction of the ball rolling from the higher level to the lower level. We then graphed this. It was a fun lab the metal balls were shiny and pretty :).

Well that's Thursday now to Friday.

The first thing we did on Friday is we corrected the yellow sheet. It looked like this ( sorry I don't know how to make a table on this post):

Phenomena Supporting Argument

Rectilinear Light travels in straight lines when sun rays pass through clouds,
Propagation shadows have sharp edges.

Reflection Very hard spheres collide with very hard surfaces and bounce off
at the same angle.

Refraction When a ball rolls down a ramp from a higher surface to a lower
surface it bends toward the normal.

Dispersion When white light passes through a prism the particles of smaller
mass fall to the bottom of the spectrum.

Diffraction Newton felt that the beam bending outward from a slit resulted
from the interactions and collisions between the light particles
at the edge of the slit.

Partial Reflection/ Newton proposed the "theory of fits". "Fit" for easy reflection.
Refraction "Fit" for easy refraction. (Weak explanation).

Speed Of Light Light moves quickly in a denser medium.


Phenomena Counter-Arguments

Rectilinear No counter arguments.
Propagation

Reflection No counter arguments.

Refraction Speed of light in water is less than speed of light in air.

Dispersion All particles have the same mass.

Diffraction Grimaldi showed that a beam of light passing through a two
successive narrow slits produced on a screen a band of light slightly
larger than the width of the slits.

Partial Reflection/ How does a particle know about what is a good "fit"?
Refraction

Speed Of Light The opposite is that light moves slower in a denser medium.


So, that's the yellow sheet. We also got a worksheet that is due on Monday it's called: Contributions to the determination of the speed of light. Read pages 8-11 and choose one of the contributors to the determination of the speed of light and fill in the sheet making sure to include interesting facts.

So, that is Thursday and Friday. Hope everyone had a wonderful Halloween. See you all Monday. For Monday's scribe I choose Nicole :). Have a wonderful rest of the weekend.

Wednesday, October 29th, 2008

Hey Everybody well i was supposed to scribe yesterday but it was a test so i figured that would be too easy hehe, so instead i will scribe for today.
Today we read pages 2-7 in The Nature of Light: Part 2
Summary
Tactile Theory
who: Plato
what: light consists of "streamers" or filaments, emited by the eye. When
these streamers come into contact with an object it is possible to see
the object.
when: early Greece
Emission theory
who: Pythagoreans
what: believed that the objects sent out light beams or particles that would
ricochet off objects and enter the eye.
when: early greece
Particle or corpuscular theory
who: Newton
what: light consists of particles that travel in straight lines.
when: 17th century
Wave theory
who: Christiaan Huygens
what: light behaves like a wave
when: 17th century
Maxwell's Electromgnetic theory states that light is an electromagnetic wave that has the same properties as other electromagnetic waves. Where as Max Planck's Quantum hypothesis states that light was transmitted and absorbed n small bundles called "quanta". The Quantum mechanical theory was then developed my many scentists in the 1900's combining the particle theory and the wave theory.
Dispersion occurs when light passes through a prism and is refracted by different amounts resulting in the formation of the spectrum of colours. With the particle theory we can assume that the different colours have different masses, with violet the lightest and refracting the most, and red the heaviest and refracting the least.


And I guess I should give a scribe for tomorrow so I'm gonna let Alex Sharp do that job. Have fun :P!!!!!
Hope everyone has a great evening.