Take Home Tasks!1.Define measurement.2. Give and describe the two systems of measurement.3. What do you mean by SI?

A Glimpse in the

History of MeAsUReMEnT

Weights and measures may be ranked among the necessaries of life to every individual of human society.

owere among the earliest tools invented by man

o Primitive societies needed rudimentary measures for many tasks:

-constructing dwellings of an appropriate size and shape, -fashioning clothing and,-bartering food or raw materials.

Sumerians and Egyptians owere known to have

been the first group of people who started using measurement

othey started measuring objects

using their body parts

oEarly Babylonian and Egyptian records and the Bible indicate that

length was first measured with the forearm, hand or

finger and the time was measured by the

periods of the sun, moon and other heavenly bodies.

oThe English people also started measuring

objects in terms of body distances. They

say, for instance,a foot is equal to the measurement of the King’s foot or an inch

represents the width of a thumb or a fathom-six feet of your total

“arm span,” from one finger tip to the other.

Vitruvian Man

The English Systemo had their origins in a variety of cultures – Babylonian, Egyptian,

Roman, Anglo-Saxon, and Norman French.

o ancient digit, palm, span and cubic units of length slowly lost preference

to the length units inch, foot and yard.

o Roman contributions include in the use of 12 (the foot is divided into 12 inches) and the words from which

we derive many of our present measurement unit names.

oThe 12 divisions of the Roman “pes” or foot were called unciae.oThe yard as a measure of length can be traced back to early Saxon kings. -the word yard comes from

the Saxon word “gird” – circumference of a

person’s waist.

Tradition holds that...oKing Henry I decreed that a yard should be the

distance from the tip of his nose to the end of his outstretched thumb.

oEarly Tudor rulers established that a length of furlong is 220 yards.

oQueen Elizabeth I (16th) declared that the traditional Roman mile of 5000 feet would be replaced by one of

5280 feet, making the mile exactly 8 furlongs and providing a convenient relationship between the

furlong and the mile.

Through Royal edicts, England by the 18th century had achieved a greater degree of standardization than other European countries.

The English system were well suited to commerce and trade because they had been developed and refined to meet commercial needs.

Through English colonization and its dominance of world during the 17th, 18th and 19th centuries, the English system of measurement units became established in many parts of the world, including the American colonies.

The Metric SystemIn 1584, the book De

Thienda by Simon Stevenius was published, preparing a decimal system of units and money

In 1670, Gabriel Mouton, Vicar of St. Paul of Lyons

and an astronomer proposed a comprehensive

decimal measurement system based on the length

of one minute of arc of a great circle of the Earth.

oThen in 1790, the French Academy of Science was

commissioned by the National Assembly of

France to design a new system of units for

throughout the world.

oThe Academy created a system that was, at once,

simple and scientific.

The unit of length was to be the portion of the earth’s circumference.

Measures for the capacity (volume) and mass were derived from the unit of length, thus relating the basic units of the system to each other and nature.

Furthermore, larger and smaller multiples of each unit were to be created by multiplying or dividing the basic units by 10 and its powers. Similar calculations in the metric system could be performed simply by shifting the decimal point. Thus, the metric system is a “base-10” or “decimal” system. Metre/meter was the assigned unit of length.

-derived from the Greek word metron- “measures”.

The initial metric unit of mass, the “gram”, was defined as the mass of one cubic centimeter (a cube that is 0.01 meter on each side) of water at its temperature of maximum density.

The cubic decimeter (a cube 0.1 meter on each side) was chosen as the unit for capacity.

The fluid volume measurement for the cubic decimeter was given the name “liter”.

oThe principles of the metric system brought

order into the conflicting traditional system of

weights and measures then being used.

o15 countries subscribed to the Convention du

Metre on May 20, 1875 and through this, the

Bureau International des Poids et Measures (BIPM)

came about.

In 1960, the General Conference on Weights and Measures, the diplomatic organization made up of the signatory nations to the Meter Convention, adopted an extensive revision and simplification of the system. Seven units were established as the basic units for the system:

1. Meter for length (m)2. Kilogram for mass (kg)3. Second for time (s)4. Ampere for electric current (A)5. Kelvin for thermodynamic temperature (K)6. Mole for the amount of substance (mol)7. Candela for luminous intensity (cd)

oIntroduced in 1960 and is adopted by many countries as the official and legal system of measurement.

The name Systeme International d’Unites (International System of Units), with international abbreviation SI, was adopted for this modern metric system.

Physical Quantities and their Units

Length-may be expressed as the interval or distance between two points. In 1983, the meter was defined as the length of path traveled by light in a vacuum.Mass-the amount of matter in any chosen object.Kilogram is defined as the mass of substance as compared to that of a standard cylinder of platinum-iridium alloy, which is kept in the International Bureau of Weights and Measures.

Weight-the force exerted by gravity on an object

Time-the interval between two events at the same place in space.

Amount of substance-mole is the amount of substance of a system

Electric current-any continuous system wherein electrons flow from the point of lowest potential to the point of highest potentialAmpere is the basic unit of electric current. It is named after the French physicist Andre Ampere (1775-1836)Thermodynamic temperature-the average kinetic energy in molecules or atoms of substances. Kelvin is defined as 1/273.16th of the thermodynamic temperature of the triple point of water.

Luminous Intensity

-is an expression of the amount of light power emanating from a point of source. Candela is defined as the intensity of a source of light of a specified frequency, which gives a specified amount of power in a given direction.

Derived Units-combination of base units produce derived unitsArea

-the measurement of the extent of a surface and is measured by multiplying the length by the width.

Volume-the space occupied by a body and is measured by multiplying the length (width) by the height.

Temperature-condition of a body that determines the transfer of heat to or from other bodies.

4 main temperature scales:DG Fahrenheit (1686-1736), a German physicist, called the freezing point of water 32 degrees and the boiling point 212 degrees.Anders Celsius (1701-1744), a Swedish astronomer, proposed the 100-degree scale

William Thomson, 1st Lord Kelvin (1824- 1907),

-a Scottish Mathematician and physicist, worked with J.P. Joule in about 1862 and produced an absolute scale of temperature. Their work gave birth to the idea of absolute zero, whose value is -273.15 degrees on the Celsius scale.

William J. M. Rankine (1820-1972),

-a Scottish engineer and scientist promoted the Kelvin scale in its Fahrenheit form, when the equivalent value of absolute zero is -459.67 degrees Fahrenheit.

Density-the ratio of mass in grams and volume in cubic centimeter, making the unit of density g/cm3