1) The document discusses dimensional analysis and similitude, which are qualitative techniques used in many fields of science and engineering. 2) Dimensional analysis involves identifying the fundamental dimensions involved in a physical phenomenon and representing the phenomenon in terms of dimensionless parameters. This allows experiments to determine the nature of relationships. 3) An example of dimensional analysis of flow velocity V in terms of gravitational acceleration g, height h, and kinematic viscosity ν is shown. Dimensionless groups like the Froude and Reynolds numbers are derived.