A venturi meter is a device used to measure the flow rate of fluids in a pipe. It operates on the principle of fluid dynamics, specifically the Bernoulli's principle, which states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure. The meter consists of a tube that narrows in the middle, creating a difference in pressure between the wider and narrower sections. As fluid flows through the venturi meter, the change in diameter causes the fluid to speed up, resulting in lower pressure in the narrow section. By measuring this pressure difference, one can calculate the flow rate of the fluid. This device is commonly used in various applications, including water supply systems and industrial processes.