Saturday, October 2, 2010

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.


  1. That was a pretty good blog. Anyways,last Friday, I asked Mr. Finley a question after class and asked me to post it up. I asked him, if light goes everywhere, then why did the laser beam light only show up as a small dot on the wall, not a blob? He told me that there are a bunch of tiny mirrors in the laser. The light rays that come out of the laser all bounce off of those mirrors and are directed all in one direction. Because of the mirrors,the laser light appears in one small dot. I thought that this was interesting, so here is an explanation for anyone that was curious

  2. Technically they are lenses and not mirrors but otherwise very nice explanation!