Length Measurement

Length measurement is very common in any science experiments. But, length measurement is only one aspect of the general field of mensuration which includes length measurement, angle measurement, area measurement and volume measurement. However, since the latter three science measurements are derived from length measurements we will be concerned in this section of Science Experiment website mainly with length measurement.

For general length measurement, wood rulers or steel rulers are normally satisfactory. Wood has a smaller thermal coefficient of expansion than steel, which can be an advantage, but on the other hand steel rulers are more readily engraved for greater precision and are not susceptible to wear and tear as much as wood.

Nominal dimensions, e.g. tube and shaft diameters, are normally measured by means of machinists' calipers used in conjunction with a steel ruler. This crude method can surprisingly give somewhat accurate length measurement. For example, it is quite possible to measure the diameter of a shaft, consistently to within ±O.2 mm of its true diameter using this length measurement method.

For more accurate measurement of length, a vernier caliper or a vernier height gauge is used. A vernier caliper with its vernier scale can give an additional significant figure in the measurement that cannot be obtained with conventional rulers.

 Click here to read about Vernier Calipers.