[[Lêer:The_Leaning_Tower_of_Pisa_SB.jpeg|duimnael|Die [[Skewe Toring van Pisa]] waar die eksperiment kwansuis plaasgevind het.]]
[[Lêer:Nieuwe_kerk_20040311.jpg|regs|duimnael|Die Nieuwe Kerk in Delft, waar die eksperiment plaasgevind het]]
In 1589-92,<ref>Some contemporary sources speculate about the exact date; e.g. Rachel Hilliam gives 1591 (''Galileo Galilei: Father of Modern Science'', The Rosen Publishing Group, 2005, p. 101).</ref> het die Italiaanse wetenskaplike [[Galileo Galilei]] (toe professor van wiskunde by die Universiteit van Pisa), volgens 'n biografie deur Galileo se leerling Vincenzo Viviani, wat hy in 1654 saamgestel en in 1717 gepubliseer het, twee sfere met verskillende [[Massa|massas]] uit die [[Skewe Toring van Pisa]] laat val om te wys dat die tyd wat hulle geneem hetneem om te val, onafhanklik wasis van hulle massa, volgens 'n biografie deur Galileo se leerling Vincenzo Viviani, wat hy in 1654 saamgestel en in 1717 gepubliseer het.<ref>[//en.wikipedia.org/wiki/Vincenzo_Viviani Vincenzo Viviani] (1717), ''Racconto istorico della vita di Galileo Galilei'', p. 606: [...dimostrando ciò con replicate esperienze, fatte dall'altezza del Campanile di Pisa con l'intervento delli altri lettori e filosofi e di tutta la scolaresca... [...Galileo showed this [all bodies, whatever their weights, fall with equal speeds] by repeated experiments made from the height of the Leaning Tower of Pisa in the presence of other professors and all the students...].</ref><ref name="Drake">{{Cite book|last=Drake|first=Stillman|date=2003|title=Galileo at Work: His Scientific Biography|edition=Facsim.|publisher=Dover publ.|location=Mineola (N.Y.)|isbn=9780486495422}}</ref>{{rp|19–21}}<ref>{{Webaanhaling|url=http://www.hindu.com/seta/2005/06/30/stories/2005063000351500.htm}}</ref><ref>[http://brunelleschi.imss.fi.it/itineraries/biography/VincenzoViviani.html Vincenzo Viviani] on museo galileo</ref>
