Being aware of the surface tension, interfacial tension of liquids and contact angles of solids is essential for many application and scientific measurements. In our lab we use the Dataphysics OCA15+ video-based optical contact angle measuring system to determine these values. Pendant drops are created on the tip of a thin needle for surface tension measurements, while sessile drops on the investigated solid surfaces are used for the determination of contact angles. The software system assists in the reliable evaluation of drop contours in combination with statistical error analysis. This method enables us the fast determination of surface tension, contact angles and the observation of adsorption kinetics on the liquid-air and liquid-liquid interfaces.