Period 2 10-12-10

Today in class we went over why when you shine the laser, only certain people at a certain angle can see it.

We had half the class stand at the front of the room, and the other half stay in their seats. The mirror was in between the two sections of people. Mr Finley shined the laser at the mirror, and some of the people in the front of the room could not see it. But the people sitting down could. Why so you think this is?

We could not see the laser on the mirror because the angle that the laser was shining at. It was bouncing off the reflective surface to the people who were sitting down.

The dot on the wall bounces off in every direction, but when we shine it at a reflective surface it will bounce off one ray at the same angle as the incident angle.

Don't forget to email Mr. Finley your lab if oyu have not all ready done so.

kk :)

Period 2 10-12-10

Today in class we we went over why when you shine the laser, only certain people at a certain angle can see it.

We had half of the class stand in front of the room, and the other half of the class stayed seated. Mr. finley shined the laser at the mirror, and some of the people in the front of the room could not see it. But the people sitting down could. Why do you think this is?

I think that because the the laser was reflecting off the the mirror and bouncing to the people on the other side of the rooms eyes, and we could not see it. The dot on the wall bounces off in every direction but when u shine it at a reflected surface it will bounce off one ray at the same angle as the incident angle.

Period 2 (10/11)

For all of the period we went over what goes into a lab report and redid any experiments we were unsure about.

Lab Report
What do you want in observations?
--Table of results, descriptions of results, general information (all 2 degrees of my prediction, etc..)
Make sure to include this in the conclusion.
--Claim, evidence, conclusion
**No need to add in curved mirror**
What would our calculations be?
--We didn't calculate anything.
What goes into the background?
--Other light experiments, things leading up to it (path of light and why do we see it(bounced off of different colors better), shone the light against the mirror, can include partner experiment with the background)
**Would be smart to include picture or drawing in results**

Uncertainty—half of the smallest division
This is helpful because when a football isn’t on the line but its half way.
Uncertainty is accurate but not precise.
Uncertainty was present in our experiment because when we measured the degrees, it was probably not exact (range). Include uncertainty in your table. **after some students were still uncertain about uncertainty, Mr. Finley did a quick drawing**

I measure something to be 45 degrees; the smallest increment is 5 degrees. What is the uncertainty?
--We find the uncertainty because it is half of the smallest increment (5/2=2.5)
+2.5 or -2.5

Does shining a laser against a mirror and it hits the opposite wall prove our hypothesis?

Law of Reflection= definitely proven
But nothing in science is proven?
--Many experiments were made, so many that it could no way be disproved.

Why can we see a dot on the mirror?
--The point on the mirror is an end point and reflects. It means that a new ray is started. (the end of one ray is also the starting point of another ray)
--The ray that hits the mirror is the strongest.

JF

Period 2 10/11/2010

Lab Report

What do you want in observations?

--Table of results, descriptions of results, general information(all 2 degrees of my prediction,etc..)

Make sure to include this in the conclusion.

--Claim,evidence,conclusion

**No need to add in curved mirror**

What would our calculations be?

--We didn't calculate anything.

What goes into the background?

--Other ligth experiemints,things leading up to it (path of light and why do we see it(bounced off of different colors better), shone the ligth against the mirror, )

**Would be smart to include picture or drawing in results**

Lasers and Light- period 2

Today we learned about how the laser reflects off of a curved mirror. How would the laser travel? The protractor has a invisible normal line, also known as 90 degrees. The formula we followed was m
Our procedures for finding the reflective ray is:

1. Place a mirror on a flat surface.

2. Put the protractor perpendicular to the mirror.

3. Shine the lazer at the mirror through the protector, perpendicular to the mirror.

4. Point the incident ray at the mirror through the protractor to get a reflective ray.

5. Repeat by starting at 10 degrees and increase by 10 degrees until you hit 90 degrees.

This was my prediction for:

10 degrees- 10 degrees

20 degrees- 20 degrees

30 degrees- 32 degrees

40 degrees- 40 degrees

50 degrees- 55 degrees

60 degrees- 63 degrees

70 degrees- 71 degrees

80 degrees- 87 degrees

90 degrees- 90 degrees



Our class data was for the actual measurement:

10 degrees- 12 degrees

20 degrees- 21 degrees

30 degrees- 30 degrees

40 degrees- 41 degrees

50 degrees- 52 degrees

60 degrees- 61 degrees

70 degrees- 70 degrees

80 degrees- 79 degrees

90 degrees- 90 degrees



S.D

Period 2

Today we went over what we did Friday and Friday's homework. We talked about what the possible outcomes were for the light going through the cardboard cut-out onto the wall. We came up with a hypothesis that it could travel in a straight line and cause the same size of the cut-out on the wall. Also, we concluded that it could fan out or just go everywhere. We found out that with just a single cut-out held against the light bulb that it goes everywhere.

Then, we visited the blog website to see how we could get to our period's blogs to see what are classmates said.

Next, we went back to Friday's homework to see how the image of the triangle cut-out got sharper as it got closer to the wall. One suggestion was that the reflection off the wall of the triangle caused the cut-out to get sharper as it got closer. We showed on the white board that one point on a single light bulb doesn't just have one ray but infinity.

Another suggestion of how the light causes the triangle cut-out to get sharper was that the light couldn't fan out once it it the cardboard which caused the triangle.

Afterwards, we went over why the candle light caused the light on the other side of the card board cut-out to appear upside down on the wall. We came up with that the rays from the candle that go through the cut-out cross each other to form itself upside down on the wall. Everything else is blocked and doesn't affect the appearance.

Today was just a review of Friday for the few people that were absent.

BB

Period 2 - Light

We needed to design an experiment for how much light can come out of one spot of a light bulb. Our materials were a knife, a light, a wall, and a piece of cardboard. We decided to cut a small hole in the cardboard, and clean it up. Then place the cardboard on the light and shine it at a wall/ roof. We would then be able to see the amount of light the comes from the one spot.



We had many ideas about how much light would come through. Some people thought 1 beam, 5 beams, 1,000 beams, 10,000 beams, 1,000,000 beams, or infinity. We believed that we would see a circle on the roof a little bigger than the cut we made in the cardboard. We thought this because the light would spread out as it came out.

As it turned out it lit up everything in a blur rather than a single focused light. It was not the circle I thought I would see. The only way we could tell any light was getting through was by holding our hand above the light to see shadows.

The light from one spot is not one single beam. It covered the whole roof. If it were one beam it would be just a dot. It was a blob covering everything. It did not slightly fan out because otherwise it would just be a circle bigger than the hole. We as a class have to agree that an infinite number of beams got through.

Towards the end of class Mr. Finley presented us with two problems to solve. The second of the two I can only guess at. The 1st is easier to understand.
1. Why when you hold the triangle there does the triangle show up and not become a blob?
I believe this happens because further from the bulb there are less beams crowded together going in all directions. This allows beams to go straight through. If they were at different angles the triangle would be distorted.
2. Why is the flame upside down.
JP