Metorology by-Dr.Ankit Srivastav

transcript

15/04/23 DR.ANKIT SRIVASTAV, EMAIL:ANKITSRIVASTAV183@GMAIL.COM 1

Metrology: Metrology is the science of weight and measures.

It encompass a study of the various systems of weights and measures, their relationships and knowledge of the mathematics Involved.

Factors influencing weight:

Temperature.

Pressure.

Altitude.

Latitude.

Definition of weight: Measurement of respective gravitational force acting upon a particular body which is directly proportional to its mass content.

Definition of Measures: It is the determination of volume or extent which particular body occupies.

Factors influencing measures:

Temperature

Pressure

Systems:

Metric system

Imperial system

Apothecary system

A. Metric System:

Definition:Internationally accepted decimal system of weight and measures.

Used In:Continental Europe.

Advantages:Unit are divided into tenth.Units of volume are comparable to units of weight.

Fundamental Units:

Unit of Length: Metre

Definition: Distance between two lines at 0 C on a platinum iridium bar (90:10) kept in the International Bureau of weights and measures in Paris.

Uses: For determination of length.

Unit of Capacity: Litre

Definition: Weight of 1 ml. of water at 4 C.Subdivide into deci, centi, milliliter.

Uses: Measurement of liquid.

Unit of Weight: Gram

Definition: Weight of 1 ml of water at 4 C.

Uses: Measurement of solid substances.

This system of weights and measures is officially practiced in India.

Chart of Different Units in Metric System:

Weights:

10 milligrams = 1 centigram

10 centigrams = 1 decigram

10 decigrams = 1 gram.

10 grams = 1 decagram.

10 decagrams = 1 hectogram.

10 hectograms = 1 kilogram.

Capacity

10 millilitres = 1 centilitre.

10 centilitres = 1 deciliter.

10 deciliters = 1 litre.

10 litres = 1 decalitre.

10 decalitres = 1 hectolitre.

10 hectoliter = 1 kiloliter.

Length:

1 millimetre = 10-3 metre.

1 centimetre = 10-2 metre.

1 decimetre = 10-1 metre.

1 micron = 10-6 metre.

Relation of Capacity to Weight:

1 litre = 1,000 ml. = 997.18 gms. (at 20 C)

IMPERIAL SYSTEM:

The Imperial System of weights and measures is commonly known as Avoirdupois System and was formerly recognized by the British Pharmacopoeia. Avoirdupois is derived from the French word “Avoir” and “Pois” which means, ‘to have weight’.

All other mass are derived from the Imperial standard pound.

Used in U.K.

Fundamental Units:

Unit of Weight:

Pound.

Ounce.

Grains.

Relation:

Unit of Volume:

[ 1 drachm = 60 minim = 4 ml.][1 oz = 30 ml. = 480 minim]

Apothecary System:

It is also known as Troy weight. The Imperial system includes a set of special weights known as Apothecaries. This system was used by the physicians in writing prescriptions and by the pharmacist in dispensing and retail trade. This system was present in U.S.A.

Fundamental Units:

Unit Weight:

Drachm

Sruples

Relation:

Pound (lb) Ounce (oz) Drachm (dr) Scruples Grains (gr)

1 12 96 288 5,760

1 8 24 480

Unit of Capacity:

Gallon

Drachm

Relation:

Gallon (gal) Pint (pt) Drachm (dr) Minim (M)

1 8 1024 61,440

Metric Imperial

1 Kilometer 0.62 miles

1 meter 1.09 yards/ 3.28 feet

1 centimeter 0.39 inches

1 millimeter 0.04 inches

1 acre 43.56 square feet

1 kilogram 2.2 pounds

1 gram 0.035 ounces

1 Liter 0.26 gallon

0 degree Celsius 32 degree Fahrenheit

Household Measures:

Household Measures English Equivalents Metric Equivalents

1 drop 1 minim 0.06 ml

1 tea spoonful 1 drachm 4 ml

1 dessert spoonful 2 drachm 8 ml

1 table spoonful 4 drachm 15 ml

1 wine glassful 2 oz. 60 ml

1 tea cupful 4 oz. 120 ml

1 tumblerful (small) 8 oz. 240 ml

Metorology by-Dr.Ankit Srivastav

Health & Medicine