The Re-Definition of the Base Units of the SI: - Using the Rules of Nature to Create the Rules of Measurement
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
GNBS International System of Units Booklet
I Table of INTRODUCTION CONTENTS The purpose of this booklet Learn About... 3 is to enable Guyanese to become familiar with • Guyana National Bureau 3 the metric system and, in of Standards (GNBS). particular, the International System of Units or SI Units. With most of the world We Look to the Future using the metric system of 5 measurements, these SI • Why do we need 5 units are now an intrinsic Measurement Standards? part of our lives. • The Role of Measurements 6 The meat, flour, fruit and in our Daily Lives. vegetables we buy; the pills, tablets and capsules doctors prescribe; the distances vehicles cover and boats Learn More On... 7 sail and athletes run, as • What is the SI? 7 well as fabric bought for our garments to be made • Why use the SI? 8 from are all weighed and measured using SI units. Given this trend, Guyana Learn the Units 9 must fully embrace metric • What are the SI Units? 9 measurements. Thus, this booklet intends to promote • The Basics of the Metric 11 a culture in which Guyanese System in use everyday. not only “think metric” but also actively use the SI units - The Kilogram 11 in their everyday lives. II III - The Kilometre 13 Guyana National - The Litre 15 Bureau of learn Standards Using the Basic Units 17 about... • Converting between Units 17 (GNBS) • Temperature 18 The Guyana National Bureau of Standards (GNBS) operates under • Writing Dates 19 the Ministry of Tourism, Industry and commerce as a semi - • Writing Times 19 -autonomous governmental organization responsible for standards and quality in Guyana. -
Operating Instructions Ac Snap-Around Volt-Ohm
4.5) HOW TO USE POINTER LOCK & RANGE FINDER LIFETIME LIMITED WARRANTY 05/06 From #174-1 SYMBOLS The attention to detail of this fine snap-around instrument is further enhanced by OPERATING INSTRUCTIONS (1) Slide the pointer lock button to the left. This allows easy readings in dimly lit the application of Sperry's unmatched service and concern for detail and or crowded cable areas (Fig.8). reliability. AC SNAP-AROUND VOLT-OHM-AMMETER (2) For quick and easy identification the dial drum is marked with the symbols as These Sperry snap-arounds are internationally accepted by craftsman and illustrated below (Fig.9). servicemen for their unmatched performance. All Sperry's snap-around MODEL SPR-300 PLUS & SPR-300 PLUS A instruments are unconditionally warranted against defects in material and Pointer Ampere Higher workmanship under normal conditions of use and service; our obligations under Lock range range to the to the this warranty being limited to repairing or replacing, free of charge, at Sperry's right. right. sole option, any such Sperry snap-around instrument that malfunctions under normal operating conditions at rated use. 1 Lower Lower range range to the to the left. left. REPLACEMENT PROCEDURE Fig.8 Fig.9 Securely wrap the instrument and its accessories in a box or mailing bag and ship prepaid to the address below. Be sure to include your name and address, as 5) BATTERY & FUSE REPLACEMENT well as the name of the distributor, with a copy of your invoice from whom the (1) Remove the screw on the back of the case for battery and fuse replacement unit was purchased, clearly identifying the model number and date of purchase. -
Units and Magnitudes (Lecture Notes)
physics 8.701 topic 2 Frank Wilczek Units and Magnitudes (lecture notes) This lecture has two parts. The first part is mainly a practical guide to the measurement units that dominate the particle physics literature, and culture. The second part is a quasi-philosophical discussion of deep issues around unit systems, including a comparison of atomic, particle ("strong") and Planck units. For a more extended, profound treatment of the second part issues, see arxiv.org/pdf/0708.4361v1.pdf . Because special relativity and quantum mechanics permeate modern particle physics, it is useful to employ units so that c = ħ = 1. In other words, we report velocities as multiples the speed of light c, and actions (or equivalently angular momenta) as multiples of the rationalized Planck's constant ħ, which is the original Planck constant h divided by 2π. 27 August 2013 physics 8.701 topic 2 Frank Wilczek In classical physics one usually keeps separate units for mass, length and time. I invite you to think about why! (I'll give you my take on it later.) To bring out the "dimensional" features of particle physics units without excess baggage, it is helpful to keep track of powers of mass M, length L, and time T without regard to magnitudes, in the form When these are both set equal to 1, the M, L, T system collapses to just one independent dimension. So we can - and usually do - consider everything as having the units of some power of mass. Thus for energy we have while for momentum 27 August 2013 physics 8.701 topic 2 Frank Wilczek and for length so that energy and momentum have the units of mass, while length has the units of inverse mass. -
Misura E Strumenti Di Misura
® MISURA E STRUMENTI DI MISURA (G) MISURA: g = G : grandezza (numero) U(G) U(G) : unita' di misura di G Come si effettua la misura ? diretta MISURA indiretta confronto diretto con unita' di misura DIRETTA: (Grandezze omogenee) con strumento "tarato" es. : termometro, voltmetro ... INDIRETTA: dalla relazione fisica con altre grandezze es. : P = F/S STRUMENTO DI MISURA: dispositivo per determinare g 30 RIVELATORE: sensibile a grandezza da misurare (sollecitazione) TRASDUTTORE: trasforma sollecitazione STRUMENTO in grandezza facilmente misurabile VISUALIZZATORE: visualizza grandezza trasformata RIVELATORE: Mercurio Es. TERMOMETRO TRASDUTTORE: Mercurio + capillare VISUALIZZATORE: capillare + scala tarata RIVELATORE: bobina mobile in campo magnetico Es. AMPEROMETRO TRASDUTTORE: movimento bobina (rotazione ago) VISUALIZZATORE: posizione ago su scala "tarata" 31 CARATTERISTICHE STRUMENTO INTERVALLO FUNZ. (valore min-max grandezza) PRONTEZZA: tempo necessario per reagire alla sollecitazione τ τ = tempo caratteristico strumento τ (termometro) ~ secondi τ (oscilloscopio) ~ 10 -9 s SENSIBILITA`: ∆R(G) dR R(G): risposta S = = ∆V(G) dV V(G): valore grandezza se R lineare in V(G): S = cost. Altrimenti S funzione di V(G) (Ohmetro) Dimensioni : [G] -1 Es. Bilancia: S in DIV/mg 32 PRECISIONE: capacita' strumento a dare stessa risposta a stessa sollecitazione MISURE RIPETUTE (sensibilit : 1/∆g) N N g(G) g(G) ∆g GIUSTEZZA: assenza di effetti sistematici Difetto strumento (termometro: capillare a sezione variabile) Uso strumento in condizioni errate (regolo -
The Revised SI for the Kilogram
Out with the Old, in with the New: The Revised SI for the kilogram Aletta Karsten, Thapelo Mametja and Henk Potgieter [email protected] Outline • Background (SI and Revised SI) • What is SI units? • Why change? • How? • When? • South African perspective • Si sphere • Kibble Balance What is a SI unit? • The SI is defined by the SI Brochure, which is published by the BIPM. • The recommended practical system of units of measurement is the International System of Units (Système International d'Unités, with international abbreviation SI). • This SI consists of a set of base units, prefixes and derived units. • The SI is not static but evolves to match the world's increasingly demanding requirements for measurement. History of SI • First milestone • Creation of the decimal metric system at the time of the French Revolution • Deposition of two platinum standards representing the metre and the kilogram, on 22 June 1799, in the Archives de la République in Paris • Signing of the Metre Convention on 20 May 1875 • Created the BIPM and established the CGPM and the CIPM • Work began on the construction of new international prototypes of the metre and kilogram. • In 1889 the 1st CGPM sanctioned the international prototypes for the metre and the kilogram. • Together with the astronomical second as the unit of time, these units constituted a three-dimensional mechanical unit system similar to the CGS system, but with the base units metre, kilogram, and second, the MKS system. Changes in measurement standards (not new) Mass Redefinition of SI • Link to fundamental constants of nature • More accurate over time 1889 https://www.bipm.org/en/measurement-units/rev-si/ Which units will be redefined? Why? • The revision of the SI will ensure that the SI continues to meet the needs of science, technology, and commerce in the 21st century. -
Guide for the Use of the International System of Units (SI)
Guide for the Use of the International System of Units (SI) m kg s cd SI mol K A NIST Special Publication 811 2008 Edition Ambler Thompson and Barry N. Taylor NIST Special Publication 811 2008 Edition Guide for the Use of the International System of Units (SI) Ambler Thompson Technology Services and Barry N. Taylor Physics Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899 (Supersedes NIST Special Publication 811, 1995 Edition, April 1995) March 2008 U.S. Department of Commerce Carlos M. Gutierrez, Secretary National Institute of Standards and Technology James M. Turner, Acting Director National Institute of Standards and Technology Special Publication 811, 2008 Edition (Supersedes NIST Special Publication 811, April 1995 Edition) Natl. Inst. Stand. Technol. Spec. Publ. 811, 2008 Ed., 85 pages (March 2008; 2nd printing November 2008) CODEN: NSPUE3 Note on 2nd printing: This 2nd printing dated November 2008 of NIST SP811 corrects a number of minor typographical errors present in the 1st printing dated March 2008. Guide for the Use of the International System of Units (SI) Preface The International System of Units, universally abbreviated SI (from the French Le Système International d’Unités), is the modern metric system of measurement. Long the dominant measurement system used in science, the SI is becoming the dominant measurement system used in international commerce. The Omnibus Trade and Competitiveness Act of August 1988 [Public Law (PL) 100-418] changed the name of the National Bureau of Standards (NBS) to the National Institute of Standards and Technology (NIST) and gave to NIST the added task of helping U.S. -
Volt-Ohm-Milliampere Meter (VOM) Content 1
2141274 Electrical and Electronic Laboratory Faculty of Engineering, Chulalongkorn University Volt-Ohm-Milliampere Meter (VOM) Content 1. Objective 2. Theoretical part 2.1) Volt-Ohm-Milliampere (VOM) meter 2.2) Color codes for a resistor 2.3) Identification of diodes and transistor polarities 3. Experimental part 3.1) Experimental instructions 3.2) Experimental report 1. Objective This laboratory helps you to familiarize with a Volt-Ohm-Milliampere (VOM) meter. 2. Theoretical Part 2.1) Volt-Ohm-Milliampere (VOM) Meter A meter with a single D’Arsonval movement that can be used to measure multiple ranges of currents and voltages is called a multimeter. A common type of analog multimetera combination voltmeter, ohmmeter and milliammeteris abbreviated VOM. The block diagram of a basic multimeter is shown in Figure 1. Moving coil type Microammeter DC Voltage Measurement Selector switch AC Voltage Measurement DC Current Measurement Test terminal Resistance Measurement Test leads Figure 1: Block diagram of a basic multimeter. The ammeter in Figure 1 is a moving coil ammeter. It uses magnetic deflection, where current passing through a coil in a magnetic field from permanent magnet creates the torque and causes the coil to move clockwise. The distance of the coil moves is proportional to the passing DC current. Figure 2 illustrates the D’Arsonval movement. 1 Figure 2: D’Arsonval movement. For DC voltage measurement, large values of resistances are connected in series with a microammeter, e.g. 50 µA, 2000 Ω, in order to limit the current passing through it. The voltage obtained can be computed from the passing current and the resistance value. -
The International Bureau of Weights and Measures 1875-1975
The International Bureau of Weights and Measures 1875-1975 U.S. DEPARTMENT OF COMMERCE National Bureau of Standards ""EAU of NBS SPECIAL PUBLICATION 420 Aerial view of the Pavilion de Breteuil and the immediate environs. To the east, the Seine and the Pont de Sevres; to the northwest, the Pare de Saint-Cloud: between the Pavilion de Breteuil (circled) and the bridge: the Manufacture Nationale de Porcelaine de Sevres. The new laboratories (1964) are situated north of the circle and are scarcely visible; they were built in a way to preserve the countryside. (Document Institute (leographique National, Paris). Medal commeiiKiraUn-i the centennial (if the Convention cif tlie Metre and the International Bureau of Weights and Measures. (Desifined by R. Corbin. Monnaie de Paris) The International Bureau of Weights and Measures 1875-1975 Edited by Chester H. Page National Bureau of Standards, U.S.A. and Pan I Vigoiireiix National Physieal Laboratory, U.K. Translation of tlie BIPM Centennial Volume Piibli>lieH on the ocrasioii <>( the lOOth Aniiiver^ai y ol tlie Treaty of tlie Metre May 20, 1975 U.S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS, Richard W. Roberts, Direcior Issued May 1 975 National Bureau of Standards Special Publication 420 Nat. Bur. Stand. (U.S.), Spec. Publ. 420. 256 pages (May 1975) CODEN: XNBSAV U.S. GOVERNMENT PRINTING OFFICE WASHINGTON: 1975 For sale by the Superintendent of Documents U.S. Government Printing Office, Washington, D.C. 20402 Paper cover Price $3.00 Stock Number 003-003-01408 Catalog Number C13.10:420 FOREWORD The metric system was made legal by Congress in 1866, the United States of America signed the Treaty of the Metre in 1875, and we have been active in international coordination of measurements since that time. -
V = Energy W Charge Q 1 Volt = 1 Joule Coulomb Dq Dt
Engineering 1 : Photovoltaic System Design What do you need to learn about? Gil Masters I. Very quick electricity review Terman 390 … but leaving town tonight feel free to email me anytime: [email protected] II. Photovoltaic systems III. PV technology IV. The solar resource V. Batteries VI. Load analysis VII. PV Sizing I’m here to help... VIII. Battery Sizing … all in one class !! ?? !! December 2, 2003 I. BASIC ELECTRICAL QUANTITIES Energy (W,joules) q (Coulombs) POWER Watts = Power is a RATE !! Time (sec) Electric Charge 1 electron = 1.602 x10-19 C dW dW dq P = = ⋅ dt dq dt P = v i dq watts Current …is the flow of charges i = charge/time = current dt energy/charge =volts e- 1 Coulomb i (Amps) = second i + ENERGY ENERGY = POWER X TIME (watt-hrs, kilowatt-hours) Voltage “the push” Watt hours = volts x amps x hours = volts x (amp-hours) energy W 1 Joule V = 1 Volt = Batteries ! charge q Coulomb 1 II. PV SYSTEM TYPES: 2. A FULL-BLOWN HYBRID STAND-ALONE SYSTEM WITH BACKUP 1. GRID-CONNECTED PV SYSTEMS: ENGINE-GENERATOR (“Gen-Set”) ….Not what you will design • Simple, reliable, no batteries (usually), 2 • ≈ $ 15,000 (less tax credits), A=200 ft for efficient house DC DC DC loads DC Batteries DC Fuse ..may want all DC, • Sell electricity to the grid during the day (meter runs backwards), buy it Charge Controller Box all AC, back at night. DC or mix of AC/DC * Sizing is simple… how much can you afford? Charger Inverter AC AC loads PVs Fuse AC AC to DC DC to AC AC • But compete with “cheap” 10¢/kWh utility grid power Generator Box AC DC Power Utility Inverter/Charger Conditioning Grid DC-to-AC to run AC loads Unit some can do AC-to-DC to charge batteries PVs AC Complex, expensive, requires maintenance, tricky to design But… competes against $10,000/mile grid extension to your house or …NOT what you are going to design 40¢/kWh noisy, balky, fuel-dependent on-site generator TRADE-OFF BETWEEN DC AND AC SYSTEMS: 3. -
Standards and Units: a View from the President of the Royal Society of New South Wales
Journal & Proceedings of the Royal Society of New South Wales, vol. 150, part 2, 2017, pp. 143–151. ISSN 0035-9173/17/020143-09 Standards and units: a view from the President of the Royal Society of New South Wales D. Brynn Hibbert The Royal Society of New South Wales, UNSW Sydney, and The International Union of Pure and Applied Chemistry Email: [email protected] Abstract As the Royal Society of New South Wales continues to grow in numbers and influence, the retiring president reflects on the achievements of the Society in the 21st century and describes the impending changes in the International System of Units. Scientific debates that have far reaching social effects should be the province of an Enlightenment society such as the RSNSW. Introduction solved by science alone. Our own Society t may be a long bow, but the changes in embraces “science literature philosophy and Ithe definitions of units used across the art” and we see with increasing clarity that world that have been decades in the making, our business often spans all these fields. As might have resonances in the resurgence in we shall learn the choice of units with which the fortunes of the RSNSW in the 21st cen- to measure our world is driven by science, tury. First, we have a system of units tracing philosophy, history and a large measure of back to the nineteenth century that starts social acceptability, not to mention the occa- with little traction in the world but eventu- sional forearm of a Pharaoh. ally becomes the bedrock of science, trade, Measurement health, indeed any measurement-based activ- ity. -
Understanding Electricity Understanding Electricity
Understanding Electricity Understanding Electricity Common units Back to basics Electrical energy The labels on electrical devices usually show one or more of the following The area of a rectangle is found by multiplying the length What flows in an electric circuit is electric charge. The amount of energy symbols: W, V, A and maybe Hz. But what do they mean and what by the width. The reason why is not hard to see. that the charge carries is specified by the electric potential (potential information do they provide? Manufacturers use these symbols to inform It takes a little more effort to see why multiplying the difference or voltage). One volt means ‘one joule per coulomb’. In summary, users so that they can operate appliances safely. In this lesson we will voltage by the electric current gives the power. the current (in amperes) is the rate of flow of charge (in coulombs per explore the meaning of the symbols and the quantities they represent 3 × 4 = 12 second); the voltage (in volts) specifies the amount of energy carried by and show how to interpret them correctly. Electric charge and electric current each coulomb. EirGrid is responsible for a safe, secure and reliable supply Symbol Unit Meaning Watts, volts and amperes If you rub a balloon on your clothes it may become of electricity: Now and in the future. electrically charged and be able to attract small C coulomb the unit of electric charge The labels on typical domestic appliances show values such as the following: bits of paper or hair. Similar effects occur when We develop, manage and operate the electricity transmission the unit of electric current, the rate of flow of amber is rubbed with cloth or fur – an effect A ampere grid. -
CAR-ANS Part 5 Governing Units of Measurement to Be Used in Air and Ground Operations
CIVIL AVIATION REGULATIONS AIR NAVIGATION SERVICES Part 5 Governing UNITS OF MEASUREMENT TO BE USED IN AIR AND GROUND OPERATIONS CIVIL AVIATION AUTHORITY OF THE PHILIPPINES Old MIA Road, Pasay City1301 Metro Manila UNCOTROLLED COPY INTENTIONALLY LEFT BLANK UNCOTROLLED COPY CAR-ANS PART 5 Republic of the Philippines CIVIL AVIATION REGULATIONS AIR NAVIGATION SERVICES (CAR-ANS) Part 5 UNITS OF MEASUREMENTS TO BE USED IN AIR AND GROUND OPERATIONS 22 APRIL 2016 EFFECTIVITY Part 5 of the Civil Aviation Regulations-Air Navigation Services are issued under the authority of Republic Act 9497 and shall take effect upon approval of the Board of Directors of the CAAP. APPROVED BY: LT GEN WILLIAM K HOTCHKISS III AFP (RET) DATE Director General Civil Aviation Authority of the Philippines Issue 2 15-i 16 May 2016 UNCOTROLLED COPY CAR-ANS PART 5 FOREWORD This Civil Aviation Regulations-Air Navigation Services (CAR-ANS) Part 5 was formulated and issued by the Civil Aviation Authority of the Philippines (CAAP), prescribing the standards and recommended practices for units of measurements to be used in air and ground operations within the territory of the Republic of the Philippines. This Civil Aviation Regulations-Air Navigation Services (CAR-ANS) Part 5 was developed based on the Standards and Recommended Practices prescribed by the International Civil Aviation Organization (ICAO) as contained in Annex 5 which was first adopted by the council on 16 April 1948 pursuant to the provisions of Article 37 of the Convention of International Civil Aviation (Chicago 1944), and consequently became applicable on 1 January 1949. The provisions contained herein are issued by authority of the Director General of the Civil Aviation Authority of the Philippines and will be complied with by all concerned.