Journal Entry 9/28

1. When light reflects off of the water of a calm pond, the incident angle is the same as the reflected angle, with respect to the normal line at that point. If a light ray were to hit a rock at 60 degrees, that rock would then reflect the ray at 60 degrees. The reflected ray would hit the surface of the calm pond at 60 degrees and be reflected once more at 60 degrees. If that same pond was disturbed by a flock of birds, the motion of the water and the figures of the birds would be reflected, as opposed to the landscape of trees and such. 3. Rays reflect off of the handle of the spoon undisturbed (the incident angle is the same as the refracted angle), so when you look at the handle through the side, nothing is changed. In contrast, the rays that hit the surface of the water before touching the spoon experience refraction. When a light ray moves from air to water, it moves away from the normal. Let's say that a ray was entering the water at an angle of 35 degrees. A normal could be created at the point where the ray hits the water. Instead of continuing straight at 35 degrees though, the angle is refracted away from the normal. The refractive index for water is 1.33, and 1 for air, so to find the degree of refraction, you would take the sine inverse of the product of the refractive index for air multiplied by the sine of 35 degrees divided by the refractive index for water. Completion of this calculation results in 25.447 degrees. This means that a light ray entering the water at 35 degrees shifts 25.5 degrees away from its normal, upon entry into the water. The principle of refraction applies to the entire portion of the spoon under the water. As a result of so many refracted light rays, pieces of the spoon look distorted when looking through the side of the cup.

Journal Entry 9/21 continued

Upon further analysis of the article, "The Role of Light to Sight", I realized that light moves in all directions from each point is not mentioned in the article. The idea that rays move from a luminous source to an illuminated object is clear, but there is no discussion as to why every one in a room can see the illuminated object. It is impossible for 50 people to stand in the same place, but regarless of where they are standing, they are all able to see a spot from a laser on the way. This is a result of many rays being projected from te luminous source, then reflected off of the illuminated object, from numerous angles. If the article had discussed this more thoroughly, a better understanding would have ocurred.

Journal Entry 9/21

A. "We are able to see because light from an object can move through space and reach our eyes". This is wrong because light does not move directly from a luminous object to your eye, it is reflected off a surface. I know that an light rays must be reflected off of a surface in order to be seen as a result of the extensive work we did with laser beams. When a laser beam is shot at the wall, the only reason I can see it is because rays within that beam are reflecting off of the wall. If this wasn't the case, I would be able to see the light of the beam in between the laser emitter and the wall. If this sentence said, "We are able to see becasue light from an object moves through space, reflects off some surface, and then reaches our eyes", it would be accurate. I studied the article for about an hour, but I couldn't find anything else wrong with it. Could you give me a hint Mr. D'Amato?

Journal Entry 9/16 continued

I believe that light rays travel in straight lines because of the experiment we performed in class with the light bulb inside of the light proof box, with only a pinhole in it. Once we turned the light bulb on and shut the lights in the class room off, an image of the light bulb appeared on the wall, but it was inverted. The only way for the image to appear like so would be if rays traveled in a straight line from the base on the bulb, throught the pinhole, to the top of the wall, and in a straight line from the top of the bulb, through the pinhole, to the bottome of the wall. If the light rays were curved, they would not have made it through the pinhole as easily, and the inverted image would not have appeared.

Journal Entry 9/16

In a completely dark room, I would not be able to see anything. If no light ray is being projected, nothing is reflecting off any object in the room. Sight is a result of a light ray being reflected off of an object, and therefore without light rays, nothing is seen. Light travels in straight lines because it cuts straight through the air, moving from its point of emission to the point at which it will be reflected. A light ray draws your eye to focus on an object, and illuminates it. You can't see objects in a dark room because no light is being reflected off of said object. The inability to see an object in a dark room, coupled with the ability to see an object in a lighted room shows that you can see an object whena light ray enters your eye. Light rays are sent in all directions from an object because you can see an object from anywhere in a room. When we experimented with the laser, Mr. D'amato could see the laser from the front of the classroom, and I could see it from my desk. This means that the light bulb sent out rays from all directions, and these rays reflected off the wall in an equally large array of directions. p

Journal Entry 9/10

Questions: 1. What is the path of light rays from the laser to the screen? How can you tell? 2. Why can you see the spot on the wall? 3. Where can you stand to see the spot on the wall? What does this mean about the rays reflected from the wall? 4. Why can’t you see the beam of light before it hits the screen? 5. What do you observe when chalk dust is sprinkled in the beam? How can you explain this? 6. Summarize the conditions necessary for you to see something. My Answers: 1. The path of the light rays from the laser are all concentrated in a straight line. There is a single, intense light that shows up in only one spot. 2. The spot of light is visible because the laser being emitted hits the wall and is reflected off of it. 3. You could stand at any spot in ther room and still be able to see the spot on the wall. This means that the rays are being reflected in every direction from the way. 4. The beam of light is not visible before it hits the screen because there is nothing for it to reflect off prior to the screen. 5. When chalk dust is sprinkled on the beam of light, the light becomes visible. This is because the light is being reflected off of the tiny dust particles. 6. In order to see something, light must be reflected off of an object. For example, light rays from a bulb reflect off of your hand and make your hand visible to you.

3.