Forward

Biography of author

Introduction

1 Measurement in Antiquity

2 Measurement in the Early Modern Period

3 Measurement in the Modern World (I)

4 Measurement in the Modern World (II)

5 Creating the language that is science

6 What was not in the original Metric System

7 Measurement in the age of scientific certainty

8 A true universal language

9 Twentieth Century confusions and refinements in measurement

10 The birth of the Quantum International System of Units

11 The base units of the International System of Units (I)

12 The base units of the International System of Units (II)

13 The basis of the Quantum-SI

14 For this is science

Weights and measures form an essential part of our ingrained view of the world, whether we realize it or not. It is near impossible to function effectively in our society without some internalized system of measurement, which enables us to estimate and judge size, weight, duration, distance and value. Our world is measured and calibrated, and we are all subject to the tyranny of these numbers, and their associated units.

In this significantly updated and extended edition of his popular book, Jeffrey Huw Williams outlines the history of the science of measurement, and the origin of the world's measurement system - the Metric System. Today, the Metric System is known as the International System of Units or SI (from the abbreviation of its official French name, Système international d'unités). The reader will discover how the turbulent early history of the Metric System owed more to revolutionary politics than to good science clearly communicated to the people for whom the new units were intended. The simplicity and coherence of the SI is outlined, and we see how a system of weights and measures, based on only seven fundamental quantities, can be used as the basis of all science; the means of defining the make of all things. This history also demonstrates the importance of effectively communicating scientific advances.

Since the previous edition, the base units of the SI have been redefined; realizing a 150-year-old dream for a measurement system based on unchanging, fundamental quantities from nature. This change has created a new SI, a Quantum SI. This new SI will significantly change the way we look at nature in a quantitative manner, and will greatly facilitate the advance of science.

Following a PhD in chemical physics from the University of Cambridge, Jeffrey Huw Williams worked as a research scientist in the universities of Cambridge, Oxford, Harvard and Illinois, and subsequently as a physicist at the Institut Laue-Langevin, France. Leaving research, Williams moved to the world of science publishing and the communication of science by becoming the European editor for the physical sciences for the AAAS's Science and subsequently, the assistant executive secretary of the International Union of Pure and Applied Chemistry. From 2003 to 2008, he was the head of publications at the Bureau International des Poids et Mesures (BIPM), Sèvres. It was during these years at the BIPM that he became interested in, and familiar with, the origin of the Metric System, its subsequent evolution into the SI, and the transformation into the Quantum SI. At the BIPM, he was the editor of their journal Metrologia. He has written widely about science, technology, the impact of science on society and the individual for general-interest magazines such as New Scientist and for more specialized magazines (Chemistry in Britain, Physics Today, Chemical & Engineering News, Physics World and Chemistry and Industry).