This resource engages students in exploring the concept of mechanical waves through a hands-on Slinky lab. The learning objective is to define mechanical waves and demonstrate that they require a physical medium for propagation. Students will participate in initial observations by creating wave pulses using a Slinky, analyzing wave behavior under different tension conditions, and investigating what occurs when the medium is removed. The lab includes a comparative analysis of energy behavior in a physical medium versus a vacuum, encouraging students to formulate scientific arguments using the Claim-Evidence-Reasoning (CER) framework. Additionally, an extension task prompts students to predict the medium that enables the fastest wave travel, reinforcing their understanding of wave propagation in solids, liquids, and gases.