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Introduction:
Measuring is essentially a process of comparison. To determine how many times a standard amount of a physical quantity is present in the quantity being measured, we must first determine how many times a known standard amount of the physical quantity appears in the quantity being measured. The magnitude of the physical quantity is the number acquired, and the unit of the physical quantity is the standard chosen. A basic, arbitrarily chosen, universally recognized reference standard known as a unit is used to measure any physical amount. The outcome of a physical quantity measurement is stated as a number (or numerical measure) followed by a unit. Although the number of physical quantities appears to be enormous, we use only a small number of units to describe them collectively since they are all connected. Fundamental or basic units are the units for base quantities. All additional physical values have units that are combinations of the foundation units. The derived units are the units obtained for the derived quantities. The system of units refers to the whole collection of these units, including both basic and derived units.
Let’s look at the International System of Units now that we’ve learned about the relevance of units and measures. People did not have any measuring instruments to compute standard measurement units in the past. To solve this challenge, people devised a variety of creative ways to measure using the instruments at hand. They used a foot as a length measurement, for example, 1 foot is approximately 0.3 metres or 30 centimetres. A league was another length measurement utilised by our forefathers. When we walked for an hour, one league equalled the distance reached by a person.
To address the problem of disparate measuring systems (much like disparate languages), the International System of Units was devised, and most industrialised and developing nations have embraced it.
Length
A ruler is a tool used in areas like geometry and technical drawing to measure lengths and distances as well as create straight lines. Both the ruler and the calibrated equipment used to calculate length are referred to as rulers, while an unmarked rule is referred to as a straightedge. Only the term, tape measure, an instrument that can be used to measure but not to draw straight lines, preserves the usage of the word measure in the sense of a measuring tool.
Time
Time is represented by numbers, names, or periods such as hours, weeks, days, and years. Time is a non-spatial continuum that is an abstract measurement of elemental changes. Within this non-spatial continuum, it is an irreversible chain of events. It’s also used to indicate the distance between two places on this continuum. The only thing visible to us is a watch with an arrow indicating the hours, minutes, and seconds.
Mass
The fundamental property of all material things to resist any change in momentum is referred to as mass. The downward force produced when a mass is in a gravitational field is referred to as weight. The ounce, pound, and tonne are Imperial mass units. The metric units of mass are grams and kilograms, and both are mass units. A weighing scale is one type of instrument for determining weight or mass. A spring scale measures force but not mass, whereas a balance compares weight, and both operate in the presence of a gravitational field. Load cells with a digital read-out are among the most precise equipment for measuring weight or mass, but they require a gravitational field to work.
Measurement
The measuring procedure is essentially a comparison process. To determine how many times a standard amount of a physical quantity is present in the quantity being measured, we must first determine how many times a standard amount of that physical quantity appears in the quantity being measured. The magnitude of the number obtained is termed as the measurement of the physical quantity, and the standard used is called the unit of the physical quantity.
MEASUREMENT OF TIME
A clock is required to measure any time. We currently employ an atomic time standard based on periodic vibrations produced in the caesium atom. This is the foundation of the caesium clock, also known as an atomic clock, which is utilised by national standards. Many laboratories have such standards on hand. The pace of this caesium atomic clock is controlled by the vibrations of the caesium atom, just as the vibrations of a balance wheel controls the rate of an ordinary wristwatch or the vibrations of a tiny quartz crystal controls the rate of a quartz wristwatch.
MEASUREMENT OF MASS
The fundamental feature of matter is mass. It is independent of the object’s temperature, pressure, or position in space. When stated in the unit of Js, which is equal to kg m2s –1, it is defined by taking the fixed numerical value of the Planck Constant h to be 6.62607015 x 10–34, where the metre and the second are specified in terms of c (speed of light) and vCs (caesium frequency). A kilogram is an awkward unit when working with atoms and molecules. In this situation, the unified atomic mass unit (u) has been devised for expressing the mass of atoms as 1 unified atomic mass unit = 1u = (1/12) of the mass of an atom of carbon-12 isotope (6C12) including the mass of electrons = 1.66 x 10–27 kg. A common balance, such as the one seen at a grocery store, can be used to determine the mass of widely accessible things. Large masses in the cosmos, such as planets and stars, may be measured using the gravitational technique, which is based on Newton’s law of gravitation. We utilise a mass spectrograph to measure minuscule masses of atomic/subatomic particles.
MEASUREMENT OF LENGTH
Some straightforward ways for measuring length are already familiar to you. For lengths ranging from 10–3m to 102 m, for example, a metre scale is employed. For lengths with an accuracy of 10–4 m, vernier callipers are used. Using a screw gauge and a spherometer, you may measure lengths as short as 10–5m. We employ certain specific indirect methods to measure lengths outside of these ranges. Large distances, such as the distance between the earth and a planet or star, cannot be measured directly on a metre scale. A parallax approach is a useful tool in such situations. When you hold a pencil against a certain point on the backdrop (a wall) and look at it through your left eye A (closing the right eye) and then through your right eye B (closing the left eye), you’ll notice that the location of the pencil changes with regard to the point on the wall. This is known as parallax. The foundation is the distance between the two locations of observation. The distance between the eyes serves as the foundation in this case.
Conclusion
Finally, performance assessment is critical in generating public value through good strategic management. Developing and refining performance measuring systems necessitates consideration of philosophical, normative, scientific, and cognitive challenges. The capacity to precisely quantify physical qualities has arguably enormous survival value, providing humans with an adaptive, evolutionary advantage that has been refined over thousands of years of natural selection.
