Viscometer Ostwald

The Ostwald Viscometer is a classic laboratory instrument used to measure the viscosity of liquids by timing how long it takes a defined volume of liquid to flow through a narrow capillary tube under gravity.

It consists of a U-shaped glass tube with two reservoir bulbs connected by a capillary and marked timing points. The liquid sample is drawn into the upper bulb and then allowed to flow down the capillary; the time taken for the meniscus to pass between two marks is recorded and used to calculate viscosity based on density and efflux time, using a calibration constant or a reference liquid like water. The Ostwald viscometer is valued for its simplicity, accuracy, and ability to yield reliable readings for Newtonian fluids in research, industrial, and educational settings.