Defining and Measuring Nature (Second Edition)

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.