Most students find real-world examples of harmonic oscillations interesting. Besides, normal and friction forces are the types of concepts in physics that are readily applicable to their everyday life. For instance, we depend on these forces to write, to drive cars, to pick up objects, and even to walk! And yet introductory physics students have too many misconceptions about them. Therefore, clarifying both forces with demonstrations is essential. In this paper, I will introduce an experiment that incorporates normal force, friction force, and oscillations. The demonstration will also confirm that sliding friction is proportional to the magnitude of the normal force.