This investigation-based lesson is geared toward third through fifth grade students. The lesson presented in this article was the first of three lessons designed and taught by us for our first preservice teaching course. UTeach is a teacher preparation program for undergraduate STEM majors, which originated at the University of Austin, Texas. The first course taken by UTeach interns is STEP 1-Inquiry Approaches to Teaching. All UTeach courses promote the use of the 5E (Engage, Explore, Explain, Elaborate, and Evaluate) instructional model. We planned this first lesson by incorporating only Exploration, Explanation, and Elaboration and addressed the most basic principle of sound, which is that sounds are caused by vibrations that travel through some materials (mediums) better than others.