June 29, 2010

Today the LTC students met with the director of the Physics REU program, who showed us some past REU projects. We saw a spinning bowl of glycerin and he showed us how to derive that the shape of the the indent in the glycerin has to be a parabolic solid of revolution. This was the most interesting aspect to me because we talked about the concept on the first day at the LTC, but we did not go through a derivation. Then he showed us a simple device for measuring the force of attraction between two capacitor plates. This was interesting, but I've heard of a similar device before. The next project he showed us was supposed to demonstrate why there are high tides on both sides of the earth, instead of just the side closest to the moon. I understood the explanation for this one the least and why the model works even less so. The basic demo was three balls suspended radially at the end of a stick, which spun. I'm still not sure how this represents the earth and the moon's affects on the water. The next demo was of Poisson's spot. The demo after that was just a clever way of measuring the thermal expansion of a thin piece of wire as it was heated. Then he showed us a tank of water with sugar. The sugar was not mixed in, but instead left to slowly dissolve into the water, creating a gradient of concentration with highest being at the bottom. This created a continuous gradient of the index of refraction, as well, and when a laser beam was shinned from the bottom towards the top of the tank, due to the effects of refraction to a medium of lower index of refraction, the beam bent in what we were told was a parabolic path. All of these projects were interesting because of the simplicity of design and concept, but they weren't what I thought an REU is about.

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