Tuesday, April 8, 2008

Constanza redid the wavelength lab after school in which we measure the wavelength of laser light using a ruler. Students who previously did it got values that did not make sense, much too small a wavelength. When Constanza did it, she used a very small angle for the light hitting the ruler (> 4 degrees). The pattern showed clear maxima on the whiteboard but a lot of garbage in between. I think that with using a greater angle and having the maxima closer, it might be harder to distinguish the garbage from real maxima. Thinking that the garbage patterns were really maxima would give too many maxima for the same distance giving a wavelength that was too small. Constanza got a value of 700 nm which is pretty good.

Reviewed for the Waves test with a student led competition.

Students divided themselves into three teams and tried to answer questions posed by Jason, Brandon, and Travis.

Questions included refraction and critical angle, wave properties, a Doppler Effect problem with echoes (how many reflections to get above a certain frequency from a car moving towards a wall), which diffracts more: an audible sound wave or a radio wave.

Everyone did a great job!!