Which of the following is a common method for measuring the pressure of a fluid?

A manometer is widely recognized as a common method for measuring the pressure of a fluid. It operates based on the principle of balancing the fluid pressure against a column of liquid, typically mercury or water. By measuring the height difference between the liquid columns, one can determine the pressure exerted by the fluid being studied. This technique is especially useful for measuring relatively low pressures and is common in laboratories and various industrial applications.

In contrast, a flow meter is primarily used to measure the flow rate of a fluid within a system, not its pressure. While some advanced flow meters might indirectly give information related to pressure by indicating flow changes, they do not directly measure pressure.

A thermometer serves a different purpose by measuring temperature, completely unrelated to pressure measurement.

A hydrostatic scale might measure weight or force in relation to the fluid's hydrostatic pressure but is not typically classified as a direct method for measuring fluid pressure itself.

Understanding these distinctions clarifies why the manometer is the preferred and recognized tool for direct pressure measurement in various settings.