The flows can be characterized as: laminar or turbulent flow; uniform or transient and compressible and incompressible. The Reynolds number is an important dimensionless quantityin fluid mechanics, that is used to help predict flow patterns in different fluid flow situationss, being defined by the ratio between inertial forces and viscous forces. The present work had as objective to use a didactic experiment of the Chemical Engineering Laboratory course, specifically Fluid Mechanics, to evoke the following concepts seen in the classroom, as well as: A) hydraulic diameter; B) Reynolds number; C) mass flow and volumetric flow; D) average flow velocity; (E) continuity equation, and visualize the different flow regimes: laminar, transition and ...