Physics: Closed Pipes

Students whiteboarded and discussed their results from yesterday’s lab on closed pipe resonators. They pretty easily recognized that, since the graphs of tube length vs. wavelength consistently have a slope near 0.25, 1/4 of the wave must have “fit” into the tube to produce a standing wave. This lab is traditionally used to find the speed of sound, but I always ended up just giving them length = wavelength/4, which bugged me. By having students use the lab to find that relationship, they only needed to use relationship between speed, wavelength, and frequency they found using snakey springs and the speed of sound, which they found using both a Direct Measurement Video and a Vernier microphone.

Chemistry: Percent Yield

Students continued working on their percent yield problems today. We spent some time discussing the physical meaning of the numbers they were using, especially the numbers in the balanced chemical equation and the molar masses since confusion about what those represent lead to a lot of the struggles students had on yesterday’s quiz.