U-tube, often referred to as a U-shaped tube, is a simple device used in various scientific experiments and applications. It consists of a tube bent into a U-shape, allowing for the measurement of fluid levels or pressure differences between two connected columns of liquid. In physics and engineering, U-tubes are commonly used in manometers to measure gas or liquid pressure. They can also be found in heat exchangers and other systems where fluid dynamics are important, helping to visualize and analyze the behavior of fluids in different conditions.