Bernoulli's principle has several practical applications, such as Bunsen burners, perfume bottles, and fire hose nozzles. A venturi tube is one such application, used to measure the velocity of a fluid flowing in a pipe. It consists of a converging part, the throat, and a diverging part. Two thin vertical tubes are connected to a venturi tube—one before the converging part and one at the throat region. Its working is based on the continuity equation and Bernoulli's principle. According to the continuity equation, if the pipe's cross-sectional area decreases, the velocity of the flow must increase. According to Bernoulli's principle, the increase in flow velocity is accompanied by a decrease in pressure. So, the pressure near the inlet is high, and the pressure at the center of the throat region is low. The height difference in the level of fluid in the vertical tubes is the measure of pressure difference. If the cross-sectional areas are known, one can solve these equations to obtain the velocity of the fluid flowing through the tube.