Title: Galileo’s Pendulum – From the Rhythm of Time to the Making of Matter
Author: Roger G Newton
Publisher: Viva Books, India 2005 (First published 2004)
ISBN: 81-309-0011-4
Pages: 137
This nice little book is authored by Roger G Newton, who is Distinguished Professor Emeritus of Physics at Indiana University. Contrary to what the reader thinks on seeing the book, the significance is on the second term – pendulum – or rather the science behind it. Galileo only makes a fleeting appearance in the text. It is a meritorious effort at discerning the order personified by harmonic working of the pendulum and the amazing discoveries and inventions to which it eventually led. All physics which came later than Galileo is heavily swayed by simple harmonic concepts which lies at the heart of the pendulum. Even quantum mechanics, the incomprehensible sibling formed during the 20th century can’t stand aloof from a liberal diffusion of the essential concepts. However, in order to avoid the fate of any book looking for only the hefty theories which came across the span of three or four centuries, Newton gently expands the horizon and let in light from diverse fields of science like biology and even some history thrown in. What emerges at the end from this seemless blend of multidisciplinary approach is a fruit which tastes so delicious.
Timekeeping is an innate feature of all living beings. A biological clock ticks inside every animal which is trained and reset frequently by sunlight so that it doesn’t go out of step. This rhythm is called the circadian (circa around, dien day) system, that runs with an approximately 25-hour cycle. It is exactly this 1-hour difference that is reset by solar light patterns like sunrise and sunset. Not only humans, birds, bacteria and plants also exhibit time-synchronous behaviour. When men began to live together in groups and tribes, established orders were introduced to keep track of flowing time for various purposes such as oblations to gods, astrological practices and agricultural activities. Babylonians brought out the first calendar based on 365 days. The torch was handed over to the Romans, with Julius Caesar essentially formulating the basis for the calendar which we see today in 46 BCE. Augustus reformed in 8 BCE by renaming the sixth month Sextilis after his own name – August. To avoid bad luck ensuing from having an even number of days (it earlier had 30 days), Augustus took one day from February (which was swinging from 29 to 30). Even with these reforms, a slight error persisted. The year really had 365.2422 days, instead of 365.25, the error began to accumulate. In 1582, Pope Gregory XIII further improved the calendar by striking off 11 days from it – Oct 15 came after Oct 4 in that year. England reformed in 1752, Sept 14 came after Sept 2. Russia changed over in 1917, after the October Revolution, which curiously occurred in November. However, religious orders like Russian Orthodox, Muslim, Jewish and Hindu still cling stubbornly to outdated and erroneous calendars.
After setting out days, men looked for instruments to measure hours and minutes. Water clocks called clepsydra were developed during the time of Archimedes. Anyhow, water was not suitable for reckoning time in the northern latitudes because of extreme cold and subsequent threat of freezing. Mechanical movements were employed for these countries. These were often elaborate constructions, but with poor accuracy. A reliable mechanism to produce accurate, periodic movement was needed. Galileo discovered the property of isochronism in pendulums – the period of oscillation is the same irrespective of the speed at which it is moving. Legend goes on to say that a bored Galileo during a service in the cathedral of Pisa observed the swing of chandeliers in the gentle breeze and timed the movement by counting his own pulse. The clock built on his design still works on the clock tower of Palazzo Vecchio in Florence with an accuracy of 1 minute in a week. The perfection in clocks came with Christiaan Huygens who is regarded as the father of modern pendulum clock. Invention of main springs helped make the watches compact enough to be kept in one’s pocket. Clocks of varying precision were developed over the ages, with atomic clocks employing cesium-133 setting the standard.
From pendulums, the author swings his attention to simple harmonic motion, the underlying principle of pendulums. Isaac Newton founded the theoretical precepts for this path of science, embellished later by 19th century physicists like Maxwell. One thing led to another with Albert Einstein and quantum mechanical revolution around the third decade of 20th century being remembered as one of the most fruitful era in the entire history of science. Harmonic oscillators form the backbone of vibrating superstrings, the new avatar in Physics’ quest for a theory of everything.
The book is richly endowed with a lot of diagrams and illustrations. The author’s professional acumen of teaching with the help of diagrams have come in handy in his venture as an author too. The book presents a very good coverage of the history of timekeeping showing an appealing blend of history and physics. Though depth is lacking – as can be expected from popular book – the breadth is enormous and readers are free to research further with seeds of ideas provided by the work.
Nevertheless, the long chapter on biological timekeeping is a bit tedious and generally not very much sticking to the theme of the work. Though the author acknowledges his indebtedness to biologists “for discussions and advice on matters in their fields of which, as a physicist, I was ignorant” (preface), the book covers a disproportionate amount of not quite relevant biological information. Readers wonder why he goes to unnecessary detail on a topic which is alien to the author as well. A case in point is the part on migratory birds. He claims that they are able to navigate using their innate timer (p.11). This is in doubt, however. Established opinion suggest that they use earth’s magnetic field to find their way.
Author’s attempt to mathematically derive the period of pendulum is tedious and unkind to the non-mathematical reader (p.88-91). Anyway, he issues a warning before proceeding with it that readers who are allergic to math may skip those pages. Moreover, the book lacks a steady focus. The title suggests a more pointed and structured approach, but it ends up exploring a vast ocean of ideas in physics, reaching nowhere in the end. Readers struggle to find out what really prompted Roger G Newton to write such a pointless book.
The book is highly recommended.
Rating: 3 Star
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