METROLOGY
In the modern society which is technology based, there are several interacting systems which affect the quality of life. Some of these systems are clearly visible in everyday life. Familiar examples are, the political system, the legal system, the educational system etc; all of which may be included under the general heading of social systems. However, there is a system which is very vital for the quality of life but not visible by itself. This is the Measurement System of a country which, in a way, pervades all other systems. We need the measurement system to provide a quantitative basis in measurement for taking decisions in all aspects of our daily life - public affairs, trade, commerce, industry, science and engineering etc.
Just as social systems have evolved in a country so has the National Measuring System. The more industrialized the country the greater the part played by the measurement system. The more industrialized the country the greater the part played by the measurement system. All scientific work is done today according to the SI System.
We make measurements to increase our knowledfe and understanding of the world we live in and to use that knowledge to help us have a better life. Metrology, which is the Science of Measurements, is vital to Trade and commerce and is a basis of modern science and technology and, consequently, of modern civilization. But what is this science of measurement and how did it begin?
Human life began on thes planet millions of years ago. For the most part man lived as apart of nature - hunting for food and sheltering in hollow trees and caves. His existence depended on the availability of plants and animals in his nearby vicinity and his ability to collect and catch them. We could question the need for measurement in these primitive societies. Maybe one might want to convey to his friends how far he travellid that day, how big was the new lake he discovered, the new cave he found or even how far he could throw a stone. In these times, obviously, only approximations could be made. Naturally he must have looked at his body and discovered his arm, hand and foot as convenient means of measurement.
There is a popular story of how the unit of length came to be the foot in the olden days. The king decided that in his empire the unit of length would be the length of his foot. Having accepted the length of the foot of the king as the primary unit of length (foot) the difficulty now is to enforce it over the whole kingdom. Since the king could not be available everywhere at all times, and different persons feet would differ in length, one more bright idea was needed - how to transfer the accurate length for everyday use at different places. This bright idea was to use a piece of wood or some other material as the unit of length. The yard was as the distance between the tip of the nose and the tip of the finger of the stretched arm - not exactly three times a foot but adjusted slightly. Because he could measure, man could become a carpenter, technician, astronomer, navigator, scientist etc. So the concept of measurement, more than everything else, has been responsible for the tremendous advance man has made from the early hunting, civilizations.
The earliest recorded history of such a measurement is from Egypt. They studied the science of geometry to assist them in the construction of the pyramids. It is believed that about 3000 BC the Egyptian "cubit" their unit of length, came into being. The Royal Egyptian Cubit was decreed to be equal to the length of the forearm plus width of palm of pharoah ruling at that time. Obviously Pharoah could not be foing from place to place to use his arm for measurement. So a master was created, a block of granite, and the workers engaged in building tombs, temples, pyramids etc. were supplied with "cubic" sticks. It was decreed that each individual worker must bring his cubic stick on each full moon to be compared against the Royal Cubit Master. Failure to do so was punishable by death. The present day system of legal metrology is similar. A primary standard is kept in a fixed location, and a series of replicas are made for everyday use. These replicas must be calibrated periodically.
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