This week is the last physics 50 lab of the semester. If you haven't already done so make sure to administer SOLATES and to collect the name of the lecturer for each student.
This lab is on the speed of sound. Students measure the length of a pipe that allows standing waves to resonate for a given frequency audio signal. Using these lengths they compute the wavelength of the sound and combined with the known frequency of the audio source determine the speed of sound in air (approximately 344 m/s). They probably have not covered standing waves in class yet, so you should give a bit of background on standing waves and resonance. The attached slide is available on transparency in both lab rooms and may be helpful for this explanation.