Sept. 21-25

On Monday, we finished the discussion about rays and one particular point on the light bulb. One hypothesis was that there is one ray on the point, and it just goes in some random direction. Another was that there are a million rays, and the direction they go in is only to a certain degree. The last hypothesis was that there are infinite rays and they go in all directions. I agrred with the last hypothesis. My H-D statement is this: If the rays are infinite and go in all directions, and we put a piece of cardboard with a hole over it, then there should not be any particular area of light that is brighter. We did the experiment , and my prediction matched the actual outcome, so that means that light goes everywhere and the last hypothesis was true. This is important because it will help us understand the other concepts.

At the end of class on Monday,we saw a piece of cardboard with a hole held next to a lit candle. There was a light from the flame on the wall, but it was upside down. (We were able to tell because of the flickering.) For homework, we had to try to come up with hypotheses to explain this. We went over them the next day, and after disproving almost all of them, we were left with one: the light from the bottom went through the hole, but only some of the rays could go through, and they went up on a diagonal, and ended up higher on the wall/object; in the middle, the light could just go straight through the whole, and ended up in the middle on the wall; at the top of the flame, the light had to go diagonal down to get to the hole, and kept going in a diagonal until it got to the wall, where it ended up below the hole. That night for homework, using this new knowledge, we had to explain how a camera worked. This is useful because now we understand how things like a camera and an eye work.

On Wednesday, we started doing some stuff with mirrors and lasers. My hypothesis from before we stared playing with the mirrors and lasers is that the light from the laser will reflect off the mirror. (I know it's not very detailed.) What happened was the laser did reflect off the mirror, but not like it reflects off the wall and other objects. Also, the dot on the mirror was not as bright to everyone as the dot on the wall. The hypotheses that we came up with to explain this were these: 1). The light from the laser is going in a very specific direction, unlike other lights, and when it reflects off the mirror, the rays continues to go in a straight line, and not just anywhere. And if it goes in a specific direction, it does mean it goes directly into your eye like other laser light rays that reflect off the wall and go everywhere. 2). Certain surfaces have different levels of reflectivity, and some will scatter the laser rays more than others. (End of hypotheses.) For homework, and also on Thursday, we designed experiments to test these. The test for reflectiveness was this: Shine a laser on the object being tested and see if it will reflect a dot onto a piece of cardboard. Then we compare the dots that were reflected onto the cardboard from all the objects and judge which were brighter, ect. We also had an experiment for the 'rays off the mirror in one general direction' hypothesis, but I forgot to write it down, and I can't remember it. We did the experiments on Friday. I only got to do the reflectiveness experiment. We're getting a little time to finish up the experiments on Tuesday (NO SCHOOL ON MONDAY!!!!! =D), so I'll just go over both experiments next week. This topic of mirrors and lasers may be useful if you need to reflect a laser around corners or in another direction.