Viscometer Ostwald

The Ostwald viscometer is a laboratory glass instrument used to measure the viscosity of liquids by timing how long it takes for a liquid to flow through a narrow capillary tube under the influence of gravity. It consists of a U-shaped glass tube with two bulbs connected by a capillary section, typically about 237 mm in overall height. The liquid is drawn into the upper bulb, and the time it takes for the liquid’s meniscus to pass between two calibrated marks on the tube is measured. This time, known as the efflux time, is directly proportional to the viscosity of the liquid. The device is calibrated using a liquid of known viscosity, such as water, allowing calculation of the viscosity of the test liquid based on relative densities and flow times. The Ostwald viscometer offers simplicity, precision, and reliability in viscosity measurement and is widely used in chemical, pharmaceutical, and research laboratories.