Introducing the notion of bare and effective mass via Newton's second law of motion

The concepts of bare and effective mass are widely used within modern physics. Their meaning is discussed in advanced undergraduate and graduate courses such as solid state physics, nuclear physics and quantum field theory. Here, I discuss how these concepts may be introduced, at a very early stage, together with the discussion of Newton's second law of motion for a sliding block. The setting up of a simple equation for the effective mass will allow instructors to discuss how external parameters, such as the temperature, influence this quantity. By developing the same equation as a power series one may also discuss perturbation theory and introduce Feynman diagrams.