Lesson 1, Topic 1
In Progress

1.8. Metric System of Measurement

ryanrori January 25, 2021

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Length10 millimetres = 1 centimetre10 centimetres = 1 decimeter10 decimetres  = 1 metre10 metres      = 1 decametre10 decametres  = 1 hectometre10 hectometres = 1 kilometre1000 metres      = 1 kilometreArea100 sq. mm     = 1 sq. cm10 000 sq. cm     = 1 sq. metre10 000 sq. cm     = 1 sq. metre100 sq. metres = 1 acre100 acres       = 1 hectare10 000 sq. metres = 1 hectare100 hectares   = 1 sq. kilometer1 000 000 sq. metres = 1 sq. kilometre
Volume1000 cu. mm = 1 cu. Cm1000 cu. cm = 1 cu. Decimeter1000 cu. dm = 1 cu. metre1 million cu. cm = 1 cu. metreCapacity10 millilitres = 1 centilitre10 centilitre = 1 decilitre10 decilitres  = 1 litre1000 litres      = 1 cu. metre
Mass1000 grams     = 1 kilogram1000 kilograms = 1 tonne

The distinction between ‘Volume’ and ‘Capacity’ is artificial and kept here only for historic reasons. A millilitre is a cubic centimetre and a cubic decimetre is a litre.

The U K (Imperial) System of Measurements

Length                   Area  12 inches   = 1 foot 144 sq. inches = 1 square foot   3 feet     = 1 yard   9 sq. feet   = 1 square yard  22 yards    = 1 chain 4840 sq. yards  = 1 acre  10 chains   = 1 furlong 640 acres      = 1 square mile   8 furlongs = 1 mile5280 feet     = 1 mile1760 yards    = 1 mile Capacity 20 fluid ounces = 1 pint Volume         4 gills        = 1 pint1728 cu. inches = 1 cubic foot 2 pints        = 1 quart  27 cu. feet   = 1 cubic yard 4 quarts       = 1 gallon (8 pints)


Mass (Avoirdupois)437.5 grains = 1 ounce Troy Weights 16 ounces   = 1 pound (7000 grains) 24 grains        = 1 pennyweight 14 pounds   = 1 stone 20 pennyweights  = 1 ounce (480 grains)  8 stones   = 1 hundredweight [cwt] 12 ounces        = 1 pound (5760 grains) 20 cwt      = 1 ton (2240 pounds)
      Apothecaries’ Measures           Apothecaries’ Weights 20 minims      = 1 fl.scruple 20 grains   = 1 scruple  3 fl.scruples = 1 fl.drachm 3 scruples = 1 drachm  8 fl.drachms  = 1 fl.ounce 8 drachms  = 1 ounce (480 grains) 20 fl.ounces   = 1 pint 12 ounces   = 1 pound (5760 grains)

The old Imperial (now UK) system was originally defined by three standard measures – the yard, the pound and the gallon which were held in London. They are now defined by reference to the S I measures of the metre, the kilogram and the litre. These equivalent measures are exact.

1 yard = 0.9144 metres – same in US1 pound = 0.453 592 37 kilograms – same in US1 gallon = 4.546 09 litres – different in US

US System of Measurement

Most of the US system of measurements is the same as that for the UK. The biggest differences to be noted are in Capacity which has both liquid and dry measures as well as being based on a different standard – the US liquid gallon is smaller than the UK gallon. There is also a measurement known at the US survey foot. It is gradually being phased out as the maps and land plans are re-drawn under metrication. (The changeover is being made by putting 39.37 US survey feet = 12 metres) 

Length               Area  12 inches   = 1 foot 144 sq. inches = 1 square foot   3 feet     = 1 yard   9 sq. feet   = 1 square yard 220 yards    = 1 furlong 4840 sq. yards  = 1 acre   8 furlongs = 1 mile 640 acres      = 1 square mile5280 feet     = 1 mile   1 sq.mile    = 1 section1760 yards    = 1 mile   36 sections   = 1 township
  Volume1728 cu. inches = 1 cubic foot  27 cu. feet   = 1 cubic yard
      Capacity (Dry)             Capacity (Liquid) 16 fluid ounces = 1 pint   2 pints   = 1 quart   4 gills        = 1 pint   8 quarts  = 1 peck   2 pints        = 1 quart   4 pecks   = 1 bushel   4 quarts       = 1 gallon (8 pints)
Mass437.5 grains = 1 ounce     Troy Weights 16 ounces   = 1 pound (7000 grains) 24 grains        = 1 pennyweight 14 pounds   = 1 stone 20 pennyweights  = 1 ounce (480 grains)100 pounds   = 1 hundredweight [cwt] 12 ounces        = 1 pound (5760 grains) 20 cwt      = 1 ton (2000 pounds)
   Apothecaries’ Measures     Apothecaries’ Weights 60 minims    = 1 fl.dram 20 grains   = 1 scruple  8 fl.drams  = 1 fl.ounce 3 scruples = 1 dram 16 fl.ounces = 1 pint 8 drams    = 1 ounce (480 grains) 12 ounces   = 1 pound (5760 grains)

As with the UK system these measures were originally defined by physical standard measures – the yard, the pound, the gallon and the bushel. They are now all defined by reference to the S I measures of the metre, the kilogram and the litre. These equivalent measures are exact

1 yard = 0.9144 metres – same as UK1 pound = 0.453 592 37 kilograms – same as UK1 gallon (liquid) = 3.785 411 784 litres1 bushel = 35.239 070 166 88 litres 

Note particularly that the US gallon is a different size to the UK gallon so that NO liquid measures of the same name are the same size in the US and UK systems. Also that the ton (US) is 2000 pounds while a ton (UK) is 2240 pounds. These are also referred to as a short ton and long ton respectively.

SI and Imperial conversions

1 Kilometre = 0.621371192237334 Miles

To convert figures from the one system to the other, you need to consult the above tables of information – similar to the following: