GALILEO'S PENDULUM

GALILEO'S PENDULUM

ROGER G. NEWTON
Copyright Date: 2004
Published by: Harvard University Press
https://www.jstor.org/stable/j.ctt13x0kt6
  • Cite this Item
  • Book Info
    GALILEO'S PENDULUM
    Book Description:

    Bored during Mass at the cathedral in Pisa, the seventeen-year-old Galileo regarded the chandelier swinging overhead--and remarked, to his great surprise, that the lamp took as many beats to complete an arc when hardly moving as when it was swinging widely.Galileo's Pendulumtells the story of what this observation meant, and of its profound consequences for science and technology.

    The principle of the pendulum's swing--a property called isochronism--marks a simple yet fundamental system in nature, one that ties the rhythm of time to the very existence of matter in the universe. Roger Newton sets the stage for Galileo's discovery with a look at biorhythms in living organisms and at early calendars and clocks--contrivances of nature and culture that, however adequate in their time, did not meet the precise requirements of seventeenth-century science and navigation.Galileo's Pendulumrecounts the history of the newly evolving time pieces--from marine chronometers to atomic clocks--based on the pendulum as well as other mechanisms employing the same physical principles, and explains the Newtonian science underlying their function. The book ranges nimbly from the sciences of sound and light to the astonishing intersection of the pendulum's oscillations and quantum theory, resulting in new insight into the make-up of the material universe. Covering topics from the invention of time zones to Isaac Newton's equations of motion, from Pythagoras' theory of musical harmony to Michael Faraday's field theory and the development of quantum electrodynamics, Galileo's Pendulum is an authoritative and engaging tour through time of the most basic all-pervading system in the world.

    Table of Contents:

    Preface

    Introduction1. Biological Timekeeping: The Body's Rhythms2. The Calendar: Different Drummers3. Early Clocks: Home-Made Beats4. The Pendulum Clock: The Beat of Nature5. Successors: Ubiquitous Timekeeping6. Isaac Newton: The Physics of the Pendulum7. Sound and Light: Oscillations Everywhere8. The Quantum: Oscillators Make Particles

    NotesReferencesIndex

    Reviews of this book:The range of things that measure time, from living creatures to atomic clocks, brackets Newton's intriguing narrative of time's connections, in the middle of which stands Galileo's famous discovery about pendulums...Science buffs will delight in the links Newton makes in this readable tour of how humanity marks time.--Gilbert Taylor, Booklist

    eISBN: 978-0-674-04148-6
    Subjects: Physics, History of Science & Technology

Table of Contents

  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-viii)
  3. Preface
    (pp. ix-xii)
  4. Introduction
    (pp. 1-3)

    He was seventeen and bored listening to the Mass being celebrated in the cathedral of Pisa. Looking for some object to arrest his attention, the young medical student began to focus on a chandelier high above his head, hanging from a long, thin chain, swinging gently to and fro in the spring breeze. How long does it take for the oscillations to repeat themselves, he wondered, timing them with his pulse. To his astonishment, he found that the lamp took as many pulse beats to complete a swing when hardly moving at all as when the wind made it sway...

  5. 1 Biological Timekeeping: The Body’s Rhythms
    (pp. 4-23)

    Imagine living on a large chunk of rock hurtling endlessly through space. It revolves neither about a central sun nor on its own axis, and it has no satellite circling it. (Never mind that such a world would lack light and heat to sustain life.) There are no mornings, no evenings, no summers, no winters, only a monotonous, temporally undifferentiated world.

    Would intelligent creatures, had they evolved there, have either internal clocks or a concept of the flow of time? The answer may well be no. Our entire notion of the passage of time is based on the perception of...

  6. 2 The Calendar: Different Drummers
    (pp. 24-33)

    Whether early humans were consciously aware of the continuous flow of time is of course impossible to tell, but it appears that this notion was firmly in place by the time civilization arose. Early civilizations had three good reasons to make use of the rhythmic nature of their experience of time: to measure the duration of a given process, such as the length of travel time from one place to another, to calculate how long ago certain memorable events took place, and to specify thenow,as well as a futurenow,for ordering their lives and their relations to...

  7. 3 Early Clocks: Home-Made Beats
    (pp. 34-47)

    For units of time smaller than a day, no natural rhythms offer guidance. The Saxons divided the day into “tides,” testimony of which remains in the “morningtide,” “noontide,” and “eventide” of poetry. But neither the Greeks, Romans, nor Chinese used a subdivision of the day until the Near East taught them about hours. From the religious or priestly point of view, the durations of the day, month, and year were dictated by the heavens and therefore by the gods; any further subdivision had to be man-made and therefore suspect.

    Presumably basing their units on a long-lost custom of the Sumerians,...

  8. 4 The Pendulum Clock: The Beat of Nature
    (pp. 48-64)

    Born in 1564, two months before William Shakespeare, Galileo Galilei ushered in the scientific component of the great period we know as the Renaissance. The son of a mathematician and musician in Pisa, he grew up to be a pugnacious and acerbic man who readily made enemies, because of his unconventional philosophical positions and his feisty personality. In the science of mechanics he argued strenuously against the prevalent Aristotelian legacy, supporting his views by experiments that are replicated to this day by students in physics courses, with objects freely falling or rolling down inclined planes. The story of his dropping...

  9. 5 Successors: Ubiquitous Timekeeping
    (pp. 65-82)

    A portable replacement for the cumbersome long pendulum—which, like the propelling weight of a clock, functioned only in an upright position and could not be easily transported or carried about—was finally invented in the second half of the seventeenth century by Robert Hooke (a man we will meet again in conflict with Isaac Newton) and our old friend Christiaan Huygens. Their invention was thecoiled balance spring. Its refined version, now sometimes called thehairspring, is a very thin steel spiral whose alternating tightening and unwinding makes a balance wheel attached to it rotate back and forth. Though...

  10. 6 Isaac Newton: The Physics of the Pendulum
    (pp. 83-97)

    Though Galileo discovered the isochronism of the pendulum as a fact of nature, he did not offer an underlying reason for his seminal observation. That explanation had to wait for the great work of Isaac Newton.

    Born after his father’s death in Woolsthorpe, Lincolnshire, on Christmas day of 1642 (January 4, 1643, according to the Gregorian calendar not yet in use in England at the time), Isaac Newton was raised mostly in his grandmother’s house. “A sober, silent, thinking lad” who grew up to be a solitary, lonely man of unpleasant disposition, he loved to tinker (building water clocks, among...

  11. 7 Sound and Light: Oscillations Everywhere
    (pp. 98-122)

    The protoscience of sound began with Pythagoras of Samos, the ancient Greek philosopher, mathematician, and mystic. He lived from ca. 560 to ca. 480 bce, but his life and teachings are known only from mutually contradictory sources written some two hundred years after his death. After traveling widely in Egypt and Babylonia, he settled in Croton in southern Italy, founding a philosophical and religious society of considerable influence.

    Pythagoras believed that “all things are numbers.” Experimenting on the strings of his lyre, he developed the theory that the most beautiful musical harmonies correspond to the simplest ratios of numbers, such...

  12. 8 The Quantum: Oscillators Make Particles
    (pp. 123-138)

    In order to understand the fundamentally new role played by Galileo’s harmonic oscillators in the physics of the twentieth century, we have to make a little detour.

    The photoelectric effect, discovered in 1897 by Heinrich Hertz, quietly initiated a revolution in physics as well as many important technological applications. Hertz demonstrated that when light falls on a metal surface, it emits electrons; if the metal is connected to an electric circuit, these electrons cause a current to flow. Five years later, Philipp Lenard found that this photoelectric effect had a surprising property: whereas the number of electrons emitted increased with...

  13. Notes
    (pp. 139-141)
  14. References
    (pp. 142-145)
  15. Illustration Credits
    (pp. 146-148)
  16. Index
    (pp. 149-153)