1) The document describes key observations used to determine internal forces (shear force Q and bending moment M) in beams using the method of sections. 2) Key observations include: forces and moments acting on a section, distribution of shear force and bending moment within beam segments, and equilibrium of forces and moments at joints. 3) The method of sections involves: determining applied loads, dividing the beam into sections, then using the observations to calculate Q and M at each section. An example application to a simply supported beam is shown.