II.2.1.1. Overview

📚 Characterization of length as physical parameter::

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Since ancient times, man has measured different lengths using as units of measure the step, elbow, palm etc.

Today, in order to have a valid unit of international length, the meter is used.

The standard meter is made of a platinum and iridium ruler, kept in special conditions, protected from moisture and temperature differences, at the International Bureau of Measures and Weights located in Sèvres (near Paris). Each country has a copy of the standard meter.

📋 Instruments used for measuring lengths:

1 – Ruler

2 – Tape line

3 – Callipers

4 – Tailoring centimeter

📚 Measuring the distance with the ruler:

When we want to measure with the ruler, we place it above the length to be measured so that the zero division is at one end of this length. To make the reading accurate, you need to make sure that the gaze falls perpendicular to the ruler, in front of the respective division.

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Indirect measurement of lengths can be done for objects we cannot reach, for rugged, swampy or water-covered terrain.

Some methods used for indirect measurement of lengths are optical methods, related to the rectilinear propagation of light. Distance reading is done on a digital screen: rangefinder (laser beam), GPS.