What is a micrometer primarily used to measure?

A micrometer is primarily used to measure thickness, providing precise measurements of small dimensions. It is an essential tool in various machining and engineering applications, where accuracy is crucial. By utilizing a screw mechanism, a micrometer can measure the thickness of materials, such as metal sheets or the diameter of small objects, with an accuracy down to a thousandth of a millimeter or more. This precision makes it essential in fields that require fine tolerances, such as automotive engineering, manufacturing, and mechanical design. The other options, which involve measuring weight, volume, and temperature, do not align with the specific functionality of a micrometer, which is focused entirely on linear measurements of small objects or material thickness.