A Brief History of Measurement

Ancient Measures

Early man used parts of the body like a forearm, hand, foot, or finger for length measurements.

To measure volume, they would fill the container with seeds and count the seeds.

As scales were invented, seeds and stones were used as standards. These were not consistent standards.

Each society had their own measurements which made it hard for trade.

English Measurement

Tradition says that King Henry I of England decreed that his foot would become the official measurement for a foot of length and that a yard would officially be the distance

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

Through royal decrees, England developed a better standardized measurement system than most other countries at that time.

There was however no relationship between the different measurements of volume, mass and length and they all have different base units.

One cannot easily convert from one measure to another without division or multiplication

English Measurement

English Customary Measures

Length = 12 inches =1 foot, 3 feet = 1 yard

5280 feet = 1 mile Mass = 1 pound = 16 ounces Volume = 1 gallon = 4 quarts, 1 quart = 2

pints

What a mess!!!

Science and Trade needed a better system

The metric system originated in France. It is based on units of 10 which allows

conversion by just moving a decimal point.

The base units for this system are – Meter (m) for length– Liter (L) for volume– Gram (g) for mass

Kilo = 1000 base units Centi=1/100 base unit Milli =1/1000 base unit

Metric Prefixes

International System of Units In 1960, an international committee

simplified the metric system into 7 basic units called SI units.– Length =Meter (m) Mass = Kilogram (kg)– Time = Second (s) Temperature = Kelvin– Amount = Mole (mol) Current = Ampere– Candela = Luminous Intensity

From these 7, all other units can be derived.