Women in Science and Engineering
Stony Brook Laser Teaching Center

Third Meeting - 27 April 2004

Today Megan and Elyssa were the only ones who showed up. Megan is from Riverhead, and this is her first meeting.

The first thing we did was look at the sky through a polarizing filter. When we looked through the filter at the sky, the glare was reduced. When we rotated the paper around, the blue sky became either darker or lighter. The polararized paper also reduced glare on a puddle of water. But - when you look through the filter directly overhead, nothing happens; you must look at the water from an angle.

When we got inside we played with the big slinky again. We looked at the difference between transverse (at a 90 degree angle) and longitudinal (parallel) waves, and nodes and antinodes. Nodes are the spots on the slinky that do not move. Antinodes are the ones that move at a 90 degree angle.

Megan and Elyssa also worked with the tuning forks and an oscilloscope examining the differences between the sine waves of different sounds and pitches. Megan produced much smoother sine curves than Dr. Noé did.

The last thing we did was look at a polarized lense in more detail. By using plastic silverware, the stress points could be seen in different colors. We looked at corn syrup, and as we rotated the polarizing filter, its color changed. One thing Elyssa found very interesting was the ability to see the light from above coming together in one point on the light box below. Megan thought hearing beats from the two tuning forks was interesting.

Elyssa left a little early, so Megan worked on one last activity. First she made a drum of sorts out of a rubber glove and a small loudspeaker. She then glued a small piece of a CD to the middle of the "drum." This drum was then hooked up to an old stereo, which was hooked up to a CD player. A laser was positioned so that it was focused directly on the small piece of the cd glued to the drum. When the music was put on, the voices created vibrations which in turn caused the laser to draw patters on the ceiling. This is the the way laser light shows are done.

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