Slow sound: An undergraduate lab experience for critical thinking

In a simple time of flight experiment, the speed of sound is observed to travel about 5% slower inside a corrugated irrigation pipe as compared with measurements conducted in open air. Although some theoretical understanding for this retardation is provided, the focus of this paper concerns how this finding might be incorporated into an undergraduate lab activity that challenges student understanding of error analysis and its significance. We propose an inquiry-based format, recently championed by others, wherein students are challenged to decide how to resolve their observation of a slower speed in a second round of investigations.