What instrument is used to measure the pressure of fluid in a tube?

The manometer is specifically designed to measure the pressure of fluids within a tube. It operates on the principle of balancing a column of liquid against the pressure to be measured, allowing for accurate readings of fluid pressure. Manometers can be used for both gases and liquids, making them versatile tools in various fields such as engineering and physics.

In contrast, a hydrometer is used to measure the specific gravity or density of liquids by observing the level to which it floats. A barometer measures atmospheric pressure using mercury or another fluid, providing readings related to weather conditions rather than fluid pressure in a confined tube. An anemometer is designed to measure wind speed and is not applicable to fluid pressure measurement at all. Each of these instruments serves its own unique purpose and is optimized for different measurements in the field of fluid dynamics.