Editing Pendulum (section)

=== 1602: Galileo's research ===
{{See also|Galileo Galilei#Pendulum}}
Italian scientist [[Galileo Galilei]] was the first to study the properties of pendulums, beginning around 1602.<ref name="Drake">{{cite book
 | last = Drake | first = Stillman
 | title = Galileo at Work: His scientific biography
 | publisher = Courier Dover
 | year = 2003
 | location = USA
 | pages = 20–21
 | url = https://books.google.com/books?id=OwOlRPbrZeQC&pg=PA20
 | isbn = 978-0-486-49542-2
}}</ref> The first recorded interest in pendulums made by Galileo was around 1588 in his posthumously published notes titled ''[[De motu antiquiora|On Motion]]'',<ref>{{cite book |last1=Galilei |first1=Galileo |last2=Drabkin |first2=I.E. |last3=Drake |first3=Stillman |title=On Motion and On Mechanics |date=1960 |publisher=University of Wisconsin |location=Madison |page=108}}</ref><ref> {{cite book | last = Drake | first = Stillman | title = Galileo at Work: His scientific biography | publisher = Courier Dover | year = 2003 | location = USA | page = 17 | url = https://books.google.com/books?id=OwOlRPbrZeQC&pg=PA17
 | isbn = 978-0-486-49542-2}}</ref> in which he noted that heavier objects would continue to oscillate for a greater amount of time than lighter objects. The earliest extant report of his experimental research is contained in a letter to Guido Ubaldo dal Monte, from Padua, dated November 29, 1602.<ref name="Galileo">{{cite book
 | last = Galilei | first = Galileo
 | title= Le Opere di Galileo Galilei, Edizione Nazionale
 | author-link = Galileo Galilei
 | editor-last= Favaro
 | editor-first= Antonio
 | editor-link= :it:Antonio Favaro
 | date = 1909
 | url = https://archive.org/details/leoperedigalile07vivigoog
 | trans-title=The Works of Galileo Galilei, National Edition
 | language=it
 | location = [[Florence]]
 | publisher= Barbera
 | isbn= 978-88-09-20881-0
}}</ref> His biographer and student, [[Vincenzo Viviani]], claimed his interest had been sparked around 1582 by the swinging motion of a chandelier in [[Pisa Cathedral]].<ref>{{cite book
 | last = Murdin | first = Paul
 | title = Full Meridian of Glory: Perilous Adventures in the Competition to Measure the Earth
 | publisher = Springer
 | year = 2008
 | page = 41
 | url = https://books.google.com/books?id=YUHyhL8MyIQC&pg=PA41
 | isbn = 978-0-387-75533-5
}}</ref><ref>[https://books.google.com/books?id=wq1aAAAAYAAJ La Lampada di Galileo], by Francesco Malaguzzi Valeri, for Archivio storico dell'arte, Volume 6 (1893); Editor, Domenico Gnoli; Publisher Danesi, Rome; Page 215-218.</ref> Galileo discovered the crucial property that makes pendulums useful as timekeepers, called isochronism; the period of the pendulum is approximately independent of the [[amplitude]] or width of the swing.<ref name="GalileoProject">{{cite web
 | last = Van Helden | first = Albert
 | title = Pendulum Clock
 | website = The Galileo Project
 | publisher = Rice Univ.
 | year = 1995
 | url = http://galileo.rice.edu/sci/instruments/pendulum.html
 | access-date = 2009-02-25
}}</ref> He also found that the period is independent of the [[mass]] of the bob, and proportional to the [[square root]] of the length of the pendulum. He first employed freeswinging pendulums in simple timing applications. [[Santorio Santorio|Santorio Santori]] in 1602 invented a device which measured a patient's [[pulse]] by the length of a pendulum; the ''pulsilogium''.<ref>{{Cite journal |last1=Bigotti |first1=Fabrizio |last2=Taylor |first2=David |date=2017 |title=The Pulsilogium of Santorio: New Light on Technology and Measurement in Early Modern Medicine |journal=Societate Si Politica |volume=11 |issue=2 |pages=53–113 |issn=1843-1348 |pmc=6407692 |pmid=30854144}}</ref> In 1641 Galileo dictated to his son [[Vincenzo Gamba|Vincenzo]] a design for a mechanism to keep a pendulum swinging, which has been described as the first pendulum clock;<ref name="GalileoProject" /> Vincenzo began construction, but had not completed it when he died in 1649.<ref>[https://books.google.com/books?id=OwOlRPbrZeQC&pg=PA20 Drake 2003], p.419–420</ref>