Formerly, the length and units of weight were founded either on a concrete object called standard (left the human body or object like a pole), or on a particular use, or on action which made it possible to measure.
In fact, measurements with this type of systems are variable (we do not have all the same “foot”). This is why, the international Système (SI) adopted definitions of units according to fixed parameters, or claimed such.
Today, of the basic units of IF, only the Kilogram is still defined in relation to a material object (the standard of the International office of the weights and measures, therefore likely to deteriorate. Research is in hand to try to find a more universal and stable definition to him.
Parts of the human body
Units of length
-
Foot: approximately 30 cm
- Finger
- Palm: in the width or the length
- Bent: elbow at the end of the fingers in general
- Brewed: measured length from one hand to another, while passing by the tended shoulders, arms
Objects
Units of length
-
Pole
The ordinary pole was worth 20 feet is 6,496 m
- Grain (weight and length)
Units of weight
-
Ton: Gallic tunna , skin of animal, which one made goatskin bottles, and whose direction passed to barrel
Action
Units of length
-
Not: distance covered in a stride
Units of area
-
Newspaper: surface that one plowed in one day (very variable!)
Speed
-
Node (of nodus in Latin): is used to measure the speed of the ships. 1 node corresponds to one thousand nautical (1852 m) per hour.
He measures himself while letting be held a climbing climbing rope (all 1/120 of mile, is 15,43 m) behind the ship during thirty seconds; each counted node (slipped by between the fingers) gives a node speed. The unit twists and small plank which is used as drift anchor calls log with boat . Initially, the thousand corresponds to the distance of one minute of arc on a parallel. In 1929, the value of the thousand is defined while being based on an average diameter of the Earth of 40000 km, that is to say 1851,85 m, rounded to 1852 m exactly (in our English friends it measures 1853,184 m).
Use
Units of volume
- Barrel: for the ships: 2,83 m ³
- Urchin: initially, quantity of wine drunk in a meal; currently, 12 beer Cl, or a half balloon of wine.
- Ration of oats: quantity of oats given to a horse (approximately 3 liters)
See too
Conversion of the units | Meter | Order of magnitude | System of measurement old | Roman Measuring units | Chinese Measuring units
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