Origins of Measurements
No civilization can escape the need for a system of measurement. Before people had measuring tools, they found points of reference such as seeds, stones and their own limbs. Dividing things into units is an ancient task. Units of measurement were among the earliest tools invented by humans. Primitive societies needed rudimentary measures for many tasks: constructing dwellings of an appropriate size and shape, fashioning clothing, or bartering food or raw materials. An inch was accepted as the distance from the tip of the thumb to the first joint; a yard was the distance from the tip of a king's nose to the end of his middle finger; a fathom was the length of a Viking's embrace. As shown in ancient German woodcuts, the length of the rod was determined by measuring the total distance covered by the left feet of sixteen men, large and small.Here are four basic numeral systems of measure and the people who first used them. You'll recognize how they are still used today.
Numeral Systems
Binary
This Hindu unit divides things into halves, quarters, and eights. Modern computer programs are based on binary code.
Decimal
The Chinese and the Egyptians were the first to use decimals, which are tenths. The metric system is based on decimal units. The decimal system of writing numbers was introduced into Europe in the 1300's and is now widely used.
Duodecimal
The Romans used units of 12. Today we have 12 inches in a foot, 12 months in a year, 12 in a dozen.
Sexagesimal
The Babylonians used units of 60. Time is measured in 60s: 60 seconds in a minute, 60 minutes in an hour.
In ancient times, the body ruled when it came to measuring. The length of a foot, the width of a finger, and the distance of a step were all accepted measurements.
Inch
At first an inch was the width of a man's thumb. In the 14th century, King Edward II of England ruled that 1 inch equal 3 grains of barley placed end to end lengthwise.
Hand
A hand was approximately 5 inches or 5 digits (fingers) across. Today, a hand is 4 inches and is used to measure horses (from the ground to the horse's withers, or shoulder).
Span
A span was the length of the hand stretched out, about 9 inches.
Foot
In ancient times, the foot was 11^{1}/42 inches. Today it is 12 inches, the length of the average man's foot.
Yard
A yard was originally the length of a man's belt or girdle, as it was called. In the 12th century, King Henry I of England fixed the yard as the distance from his nose to the thumb of his outstretched arm. Today it is 36 inches, about the distance from nose to outstretched arm of a man.
Cubit
In ancient Egypt, a cubit was the distance from the elbow to the fingertips. Today a cubit is 18 inches.
Lick
A Lick was used by the Greeks to measure the distance from the tip of the thumb to the tip of the index finger.
Pace
The ancient Roman soldiers marched in paces, which were the length of a double step, about 5 feet; 1,000 paces was a mile. Today, a pace is the length of one step, 2^{1}/2 to 3 feet.
Measurements
 Inch = 0.083 feet
 Foot = 12 inches
 Yard = 3 feet or 36 inches
 Mile = 5,280 feet or 1,760 yards
Near and Far
 Around the earth (at the equator): 24,901 miles
 Across the continental U.S.: 3,000 miles
 From the earth to the moon: 238,854 miles
 From the earth to the sun: 93,000,000 miles
Metric Weights and Measures
Most of the world uses the metric system. The only countries not on this system are the U.S., Myanmar, and Liberia.
The metric system is based on 10's. For example, 10 decimeters make a meter (39.37 inches).
Units smaller than a meter have Latin prefixes:
 Deci  means 10; 10 decimeters make a meter.
 Centi  means 100; 100 centimeters make a meter.
 Milli  means 1,000; 1,000 millimeters make a meter.
Units larger than a meter have Greek prefixes:
 Deka  means 10; a dekameter is 10 meters.
 Hecto  means 100; a hectometer is 100 meters.
 Kilo  means 1,000; a kilometer is 1,000 meters.
A millimicron is one thousandth of one millionth of one meter.
Helpful Hints:
Remember: A meter is a little more than a yard. A kilometer is less than a mile. A liter is a little more than a quart.



Metric Conversions
Multiply 
By 
To Find 
Multiply 
By 
To Find 
Centimeters 
.0328 
feet 
Meters/minute 
1.667 
centimeters/second 
Centimeters 
.3937 
inches 
Meters/minute 
.0547 
feet/second 
Feet 
30.4801 
centimeters 
Miles 
1.6093 
kilometers 
Feet/minutes 
.507 
cent./seconds 
Miles/hour 
.8684 
knots 
Footpounds 
.1383 
meterkilograms 
Miles/hour 
1.6093 
kilometers/hour 
Gallons 
3,785.4 
cubic centimeters 
Miles/hour 
.447 
meters/second 
Gallons 
3.7853 
liters 
Ounces 
28.3495 
grams 
Grams 
.0353 
ounces 
Ounces 
2.8349x10^{(2)} 
kilograms 
Grams 
.0022 
pounds 
Pounds 
453.5924 
grams 
Inches 
2.54 
centimeters 
Pounds 
.4536 
kilograms 
Inches 
.0833 
feet 
Quarts 
.946 
liters 
Kilograms 
2.2046 
pounds 
Quarts (dry) 
67.2 
cubic inches 
Kilometers 
3,280.833 
feet 
Quarts (liquid) 
57.75 
cubic inches 
Kilometers 
.6214 
miles 
Sq. centimeters 
.0011 
square feet 
Kilometers/hour 
54.68 
feet/minute 
Sq. kilometers 
.3861 
square miles 
Kilometers/hour 
.6214 
miles/hour 
Sq. kilometers 
1.196x10^{(6)} 
square yards 
Knots 
1.8532 
kilometers/hour 
Sq. meters 
10.7639 
square feet 
Liters 
1.0567 
quarts 
Sq. meters 
1.196 
square yards 
Meters 
3.2808 
feet 
Sq. miles 
2.59 
square kilometers 
Meters 
39.37 
inches 
Sq. yards 
.8361 
square meters 
Meters 
1.0936 
yards 
Yards 
91.44 
centimeters 
Meterkilograms 
7.2307 
footpounds 
Yards 
.9144 
meters 
The International System (Metric)
Source: Department of Commerce, National Bureau of Standards.
The International System of Units is a modernized version of the metric system, established by international agreement that provides a logical and interconnected framework for all measurements in science, industry, and commerce. The system is built on a foundation of seven basic units, and all other units are derived from them. (Use of metric weights and measures was legalized in the United States in 1866, and our customary units of weights and measures are defined in terms of the meter and kilogram.)
Length
Meter. Up until 1983, the meter was defined as 1,650,763.73 wavelengths in a vacuum of the orangered line of the spectrum of krypton86. Since then, it is equal to the distance traveled by light in a vacuum in 1/299,792,45 of a second.
Time
Second. The second is defined as the duration of 9,192,631,770 cycles of the radiation associated with a specified transition of the cesium133 atom.
Mass
Kilogram. The standard for the kilogram is a cylinder of platinumiridium alloy kept by the International Bureau of Weights and Measures at Paris. A duplicate at the National Bureau of Standards serves as the mass standard for the United States. The kilogram is the only base unit still defined by a physical object.
Temperature
Kelvin. The Kelvin is defined as the fraction 1/273.16 of the thermodynamic temperature of the triple point of water; that is, the point at which water forms an interface of solid, liquid, and vapor. This is defined as 0.01°C on the Centigrade or Celsius scale and 32.02°F on the Fahrenheit scale. The temperature 0°K is called "absolute zero."
Electric Current
Ampere. The ampere is defined as that current that, if maintained in each of two long parallel wires separated by one meter in free space, would produce a force between the two wires (due to their magnetic fields) of 2 × 10^{7} Newton for each meter of length. (A Newton is the unit of force that when applied to one kilogram mass would experience an acceleration of one meter per second per second.)
Luminous Intensity
Candela. The candela is defined as the luminous intensity of 1/600,000 of a square meter of a cavity at the temperature of freezing platinum (2,042°K).
Amount of Substance
Mole. The mole is the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon12.
Measuring Motion
Speed is the measure of motion. You can find it by dividing the distance covered by the time it takes to travel that distance.
Speed of Light
Light travels through space at 186,000 miles per second.
If a star is 10 lightyears away, it is about 60 trillion miles distant.
LightYear
A light ray travels 5.88 trillion miles a year in space.
Star Distance
The star Sirius is 9 lightyears away from the solar system.
More Earthly Speeds
 Cheetah: 70 mph
 Whitetailed deer: 32 mph
 Human being: 27.89 mph
 Garden snail: 0.03 mph
 Fastest automobile: 205 mph
 Fastest train: 252 mph
 Fastest helicopter: 249.10 mph
 Fastest jet: 2,193.167 mph
Measuring Power
Horsepower
A workhorse can lift 550 pounds 1 foot in the air in 1 second; that is 1 horsepower. Engines are measured in horsepower. A 10horsepower engine can do the work of ten horses.
Manpower
An average man lifts 55 pounds 1 foot high in 1 second.
Candlepower
The amount of light given off by a candle of a specific size, shape, type of tallow, and type of wick. The brightness of an electric light is measured in candlepower.
Megaton
A megaton is the blasting power of a hydrogen bomb. One megaton has the power of 1 million tons of TNT.
Nautical Measurement
A fathom is 6 feet, the length of rope a man can extend from open arm to open arm. The rope was lowered into the sea to measure depth.
A cable length is the length of a ship's cable, about 600 feet.
A nautical mile is 10 cable lengths, or 6,080 feet.
1 nautical mile = 1.1515 miles
A knot is the measure of speed on water. One knot is 1 nautical mile per hour.
Miscellaneous Units of Measure
acre
An area of 43,560 square feet. Originally, the area a yoke of oxen could plow in one day.
agate
Originally a measurement of type size (5 and 1/2 points). Now equal to 1/14 inch. Used in printing for measuring column length.
ampere
Unit of electric current. A potential difference of one volt across a resistance of one ohm produces a current of one ampere.
astronomical unit (A.U.)
93,000,000 miles, the average distance of the earth from the sun. Used for astronomy.
bale
A large bundle of goods. In the U.S., the approximate weight of a bale of cotton is 500 pounds. The weight varies in other countries.
board foot (fbm)
144 cubic inches (12 in. × 12 in. × 1 in.). Used for lumber.
bolt
40 yards. Used for measuring cloth.
Btu
British thermal unit. Amount of heat needed to increase the temperature of one pound of water by one degree Fahrenheit (252 calories).
carat (c)
200 milligrams or 3.086 grains troy. Originally the weight of a seed of the carob tree in the Mediterranean region. Used for weighing precious stones.
chain (ch)
A chain 66 feet or onetenth of a furlong in length, divided into 100 parts called links. One mile is equal to 80 chains. Used in surveying and sometimes called Gunter's or Surveyor's chain.
cubit
18 inches or 45.72 cm. Derived from distance between elbow and tip of middle finger.
decibel
Unit of relative loudness. One decibel is the smallest amount of change detectable by the human ear.
ell, English
1 and 1/4 yards or 1/32 bolt. Used for measuring cloth.
freight, ton (also called measurement ton)
40 cubic feet of merchandise. Used for cargo freight.
great gross
12 gross or 1728.
gross
12 dozen or 144.
hand
4 inches or 10.16 cm. Derived from the width of the hand. Used for measuring the height of horses at withers.
hertz
Modern unit for measurement of electromagnetic wave frequencies (equivalent to "cycles per second").
hogshead (hhd)
2 liquid barrels or 14,653 cubic inches.
horsepower
The power needed to lift 33,000 pounds a distance of one foot in one minute (about 1 and 1/2 times the power an average horse can exert). Used for measuring power of steam engines, etc.
karat (kt)
A measure of the purity of gold, indicating how many parts out of 24 are pure. For example: 18karat gold is ^{3}/4 pure. Sometimes spelled carat.
knot
Not a distance, but the rate of speed of one nautical mile per hour. Used for measuring speed of ships.
league
Rather indefinite and varying measure, but usually estimated at 3 miles in Englishspeaking countries.
lightyear
5,880,000,000,000 miles, the distance light travels in a vacuum in a year at the rate of 186,281.7 miles (299,792 kilometers) per second. (If an astronomical unit were represented by one inch, a lightyear would be represented by about one mile.) Used for measurements in interstellar space.
magnum
Twoquart bottle. Used for measuring wine, etc.
ohm
Unit of electrical resistance. A circuit in which a potential difference of one volt produces a current of one ampere has a resistance of one ohm.
parsec
Approximately 3.26 lightyears or 3.08 × 10^{13} km (1.92 × 10^{13} mi). Term is combination of first syllables of parallax and second, and distance is that of imaginary star when lines drawn from it to both Earth and the Sun form a maximum angle or parallax of one second (1/3600 degree). Used for measuring interstellar distances.
pi ( )
3.14159265+. The ratio of the circumference of a circle to its diameter. For practical purposes, the value is used to four decimal places: 3.1416.
pica
1/6 inch or 12 points. Used in printing for measuring column width, etc.
pipe
2 hogsheads. Used for measuring wine and other liquids.
point
.013837 (approximately 1/72) inch or 1/12 pica. Used in printing for measuring type size.
quintal
100,000 grams or 220.46 pounds avoirdupois.
quire
Used for measuring paper. Sometimes 24 sheets but more often 25. There are 20 quires to a ream.
ream
Used for measuring paper. Sometimes 480 sheets, but more often 500 sheets.
roentgen
International Unit of radiation exposure produced by Xrays.
score
20 units.
sound, speed of
Usually placed at 1,088 ft. per second at 32°F at sea level. It varies at other temperatures and in different media.
span
9 inches or 22.86 cm. Derived from the distance between the end of the thumb and the end of the little finger when both are outstretched.
square
100 square feet. Used in building.
stone
Legally 14 pounds avoirdupois in the U.K.
therm
100,000 BtU's.
township
U.S. land measurement of almost 36 square miles. The south border is 6 miles long. The east and west borders, also 6 miles long, follow the meridians, making the north border slightly less than 6 miles long. Used in surveying.
tun
252 gallons, but often larger. Used for measuring wine and other liquids.
watt
Unit of power. The power used by a current of one ampere across a potential difference of one volt equals one watt.
Standard Measurements in Sports:
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