Metrology The fabric of science and technology Students

Metrology: The fabric of science and technology Students Mi. VT-21

What is metrology? The science of measurement (not weather!) Metrology establishes the international standards for measurement used by all countries in the world in both science and industry Examples: distance, time, mass, temperature, voltage, values of physical and chemical constants

Why is metrology important and interesting? • Standard units and values of constants needed for all science • Technological standards make all technology work better and can save lives: fire hydrant standards • Measurement of constants can give fundamental insights into the universe: drift of fine structure constant

Who does metrology? Government labs around the world. From Article I, section 8 of the U. S Constitution: “The Congress shall have Power To… …fix the Standard of Weights and Measures; ”

SI: The International System of Units Seven base units: Lots of derived units: Length: meter (m) Area: m 2 Mass: kilogram (kg) Speed: m/s Time: second (s) Electric current: ampere (A) Force: 1 newton = 1 kg·m/s 2 Voltage: 1 volt = 1 m 2·kg/s 3·A Frequency: 1 hertz = 1/s Thermodynamic temperature: kelvin (K) Power: 1 watt = 1 kg·m 2/s 3 Amount of substance: mole (mol) Electric Charge: 1 C = 1 A·s Luminous intensity: candela (cd)

Hierarchy of units: Kings and queens of units: Time, frequency, distance Dukes and Earls: Current, voltage, resistance Peasants: Mass, temperature, pressure, luminosity

Clocks: Atomic time One part per quadrillion accuracy!!! Accurate frequency gives accurate distance and time.

Temperature: Kelvin, Celsius, and Fahrenheit 21 C 70 F 294 K 0 C 32 F 273. 15 K Water freezes -196 C -321 F 77 K Air liquefies 4. 2 K Helium liquefies -269 C -452 F -273. 15 C -459. 67 F 0 K Room temperature Absolute zero

History of Metrology • The oldest recorded Standard measure for length is the “Egyptian Royal Cubit”. It was the distance from the elbow to the tip of the middle finger of the reigning Pharaoh. This distance was carved in black granite and used as the national standard measure of length for construction. The working standards were calibrated each full moon and the errors committed in their measurements were punishable by death;

In various "Holy Books" of diverse religions, we find high religious thoughts intermingled with metrology in areas of it morale, hygiene or punishment. Many religious thoughts that relate to weights and measures serve as the basis for modern metrology regulations. For example: Bible: “A false balance is an abomination to the lord but a just weight is his delight”. Proverbs 11: 1 “Divers weights and divers measures, both are alike, an abomination to the Lord”. Proverbs 20: 10 Quoran: “In the name of Allah, the most merciful, miserable and unhappy are those who defraud in weights and measures; when they measure against others they use complete weights, but when they measure for others they reduce the weight”. The Talmud: “The merchant has the obligation to clean his measures twice a week; his weights, once a week and his balance after each weighing”.

Measurement error Deviation of measurement from the true value of the measured physical quantity. Accuracy is a quantitative characteristic measurement accuracy. Depending on the chosen classification signs are different classifications of measurement errors, among which are the most common: • Of the form of expression; • Of the sources of origin; • Of the patterns of occurrence and manifestation.

Measurement error • Absolute error of measurement - a measurement error, expressed in units of the measured value. • The relative error of measurement - a measurement error, expressed as the ratio of absolute error to the actual or measured value. • Instrumental error - component measurement error due to the properties of measuring instruments. This error in turn may contain several components, including error of measurement and uncertainty caused by the interaction of vehicle measuring one with object of measurement. • Articles error - component measurement errors due to the imperfection of the method of measurement or inadequate measurement object the model adopted for the measurement. • Operator error - component measurement errors due individual properties of the operator. According to the laws of manifestation and distinguish systematic and random errors. • Systematic error - part of the total measurement error, which remains constant or changes regularly during repeated measurements of the same magnitude. • Random error - part of the total measurement error that varies randomly (both in sign and in magnitude) during repeated measurements of the same magnitude.

By the mid-1800 s standardization joined the division of labor and machine-assisted manufacturing as well-established principles of mass production, but they were not widely applied for decades to come. Twentieth century industrialist Henry Ford (1863 -1947) was a great proponent and beneficiary of mass production. He organized the Ford Motor Co. around its principles, taking standardization to a high level. His plants manufactured only one type of car at a time. Each auto that came off the production lines was identical, even down to the color—black. Standardization not only saved on production costs, but also benefited consumers, who no longer had to have replacement parts machined by hand. Ford's success contributed to the proliferation of massproduction principles, including standardization, throughout the developed world. The concept has promoted a dramatic increase in manufacturing productivity, which in turn improved living standards. The concept of standardization has been applied in many ways since.