Kinds of Measuring Instrument

1. Ruler
A ruler, or rule, is an instrument used geometri, technical drawing and engineering/building to measure distances and/or to rule straight lines. Strictly speaking, the ruler is essentially a straightedge used to rule lines and the calibrated instrument used for determining measurement is called a "measure". However, common usage implies that a ruler is a straightedge that is calibrated for making measurements.

2. Caliper
A caliper is a device used to measure the distance between two symmetrically opposing sides. A caliper can be as simple as a compass with inward or outward-facing points. The tips of the caliper are adjusted to fit across the points to be measured, the caliper is then removed and the distance read by measuring between the tipswith a measuring tool, such as a ruler.

3. Micrometer
A micrometer sometimes known as a micrometer screw gauge, is a device used widely in mechanical engineering and machining as well as most mechanical trades for precision measurement, along with other metrological instruments such as dial caliper and vernier caliper. Micrometers are often, but not always, in the form of calipers.

4. Tape measure
A tape measure or measuring tape is a flexible form of ruler. It consists of a ribbon of cloth, plastic, fiber glass, or metal strip with linear-measurement markings. It is a common measuring tool. Its flexibility allows for a measure of great length to be easily carried in pocket or toolkit and permits one to measure around curves or corners.