Measurements - A Detailed Summary

VSAT 2022

An Overview of the Measurements

Measurement system is used to connect the number to physical quantities and processes. There were formerly four basic measurements such as mass (weight), distance or length, area and volume (liquid or grain). However, the idea of weights and measures has widened to include diverse factors like temperature, brightness, pressure, and electrical currents measured. The fundamental idea in the study of science and Mathematics is measurement.


The qualities of an object or an occurrence can be specified so that we may compare them to those of other objects or incidents. When discussing the division of a quantity, measurement is the word that appears most frequently. Additionally, in that, it requires a specific number of items to complete a specific task. We commonly experience many measurement types for length, weight, times, etc. in our daily lives. A standard unit of measurement represents the magnitude of a quantity, even though the size, measurement, and quantity all differ. This leads to the requirement for the units of measurement for every quantity.


What is Measurement?

Measurement is a method that involves the comparison of an object's characteristics to the reference value in order to identify its attributes. The primary metric for expressing any quantity of objects, things, and occurrences is measurement. Since there is no way to make a proper comparison, the measurements always contain an error, which is the difference between the measured value and the true value. Metrology is the study of measurement.


There are certain generally used standard measurement systems, such as the English System, the Metric System, and the International System of Units (SI). A metre stick can be used to measure an object's length, a graduated cylinder can be used to measure a liquid's volume, and a thermocouple can be used to measure a fire's temperature. Type, magnitude, unit, and uncertainty are among the parameters that are used to compare the measurements.


Types of Measurement and Units

Standard and non-standard measurements fall under two measurement categories. The value of the standard unit remains constant that cannot be altered with its uniformity in the measurement. In the US, the measurement is expressed in feet, inches, and pounds, but in the metric system, it is expressed in metres, centimetres, and kilograms. The benefits of using a standard unit are as follows:

  • It facilitates the understanding of measurements in a group of unit systems.

  • Without the need for conversion, SI units are generated from one another.

  • A metric system is SI. One of the SI unit's drawbacks is that it only mentions one unit. So, the significance of other units was lessened.

Nonstandard measurement includes the units like a block, an arm, a pencil, etc. that has the benefit of making measurement simpler, but it also has the drawback of being difficult for some people to understand. All the physical quantities must be measured using standard units that are defined by the International System of Units, or SI units. Any physical amount can theoretically be stated in terms of the seven basic units as listed in the table below:


The Seven Fundamental Units

Property

Unit

Symbol

Length

metre

m

Mass

kilogram

kg

Time

second

s

Electric Current

Ampere

A

Temperature

Kelvin

K

Amount of Substance

mole

mol

Luminous Intensity

candela

cd


The various measurement types that are utilised to express are listed below:

  • Time: The units to express time are minutes, hours, days, weeks, months, years, etc.

  • Length or Distance: Measuring units for length or distance are millimetres, centimetres, kilometres, etc.

  • Weight: Grams, kilograms, and other units are the weight measuring units of various objects.

  • Volume: Litres, cm3, and other units are used to express volume.

  • Temperature: Fahrenheit and centigrade are the two most units used to express the temperature.


In addition to the seven fundamental units, certain units are derived by using one or more base units. These are called derived units such as:

  • Power: watt (W)

  • Frequency: hertz (Hz)


Measurement Instruments and Scaling

Different measurement scales are available, including the nominal, ordinal, interval, and ratio scales.

  1. Nominal Measurement

This is the lowest level of scale where the numbers are used to identify or classify the objects by assigning the titles or labels to them. This scaling generally applies to non-numeric variables or inert objects.

  1. Ordinal Measurement

The second level of measurement uses an ordinal measurement scale to arrange the data without indicating how much the data vary from one another. ‘Order’ is symbolised by the ordinal. Ordinal data can be grouped, identified, and rated, sometimes known as qualitative or classified data.

  1. Interval Measurement

The third level of the measurement scale is the interval measurement scale, which is a quantitative measuring scale and allows us to express any two variables' differences.

  1. Ratio Measurement

The fourth level of the measuring scale, which is quantitative, is the ratio measurement scale. The origin, or zero points character, is a special characteristic of ratio scaling.


Uses of Measurement

For the following instances, measurement is a significant concept:

  • Right dimensions are essential during the design of construction.

  • For the exchange, purchase, and sale of items.

  • For food preparations, the materials are commonly taken in particular proportions.

  • For performing scientific experiments in laboratories.

  • To finish a particular task, time is an essential issue to consider.

  • To create medications and treat people.


Interesting Fact

  • The magnitude of the quantity serves as a standard unit and is used in a variety of measures.

  • Non-standard units like a digit, handspan, and pace were in use before the discovery of standard units of measurement.


Key Features

  • An established quantity called a measurement unit is used to represent the physical quantities.

  • There are numerous systems and units in use for measuring various quantities, including length, area, mass, and volume.

  • The International System of Units or SI units was established to tackle the problem of different measurement systems, which defines standard units for measurement of all physical quantities.

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FAQs on Measurements - A Detailed Summary

1. What are a physical quantity's dimensions?

A physical quantity's dimensions relate to its characteristics that give rise to its quantifiable criteria. The dimensions of any physical quantity can be found by the number of times the Mass, Length, and Time appear in that physical quantity. For example, Dimension of Velocity is $\left[{M^0}~{L^1}~{T^{-1}}\right]$ it implies that length and time occurred once in velocity and there is no mass term.

2. How do supplemental units work?

The supplementary units are basically a special case of derived units. Physical variables without dimensions that are employed in addition to the fundamental units are referred to as supplementary units.

3. What does the term "unit conversion" mean?

During the calculations, depending upon the requirement of the unit system, we can convert CGS to MKS or vice versa. We can convert the units if and only if they belong to the same physical quantity. Thus, a unit conversion is the process of changing a quantity's measurement among two distinct measuring units. For example, Unit of force SI unit is N and it can be written as dyne in CGS system.

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