What is a micrometer?
A micrometre (American spelling: micrometer; symbol µm) is one millionth of a metre, or equivalently one thousandth of a millimetre. It is also commonly known as a micron. It can be written in scientific notation as 1×10−6 m, meaning 1/1 000 000 m. The symbol µm’s character µ (Unicode character U+00B5; HTML µ) is “micro-“, which should look identical to the Greek letter mu (μ) (the two may or may not look the same, depending on the font). The symbol µm is sometimes replaced by “um” when a suitable glyph if/when µ is not readily available, for example in ASCII or when using a typewriter, although this is non-standard. Read more A micrometer allows a measurement of the size of a body. It is one of the most accurate mechanical devices in common use. This document introduces this instrument. If you are a student in the Physics laboratory at the University of Toronto, the material discussed here is also covered in the Commonly Used Instruments section of the First Year Laboratory Manual. Th