Willem 's Gravesande
Willem Jacob ' s Gravensande ( born September 26, 1688 in ' s-Hertogenbosch, † February 28, 1742 in Leiden ) was a Dutch astronomer, philosopher, physicist, and mathematician.
Life and work
His father, Dirk Storm van ' s Gravensande (1646-1716), was sheriff of the city of ' s-Hertogenbosch and administrators of the estates of William III. , King of England, and later of William IV, Prince of Orange. His mother was Anna Louisa Blom ( 1653-1724 ). The couple was married for 11 July 1681, it had a total of eight sons and one daughter. His maternal grandfather was John Heurnius, a professor at the University of Leiden.
At the age of sixteen years studied Willem Jacob ' s Gravensande law at Leiden University and received his doctorate in 1707 with a dissertation on the topic of suicide.
In 1715 traveled ' s Gravensande occasion of the coronation of George I as a member of a delegation from the British capital London. During his year-long stay in London, he became a member of the Royal Society, where he made the acquaintance of Isaac Newton, John Theophilus Desaguliers, and the Scottish mathematician John Keill.
1717 ' s Gravensande professor of astronomy and mathematics at the University of Leiden. The chairs for civil and military architecture and philosophy follow in the years 1730 and 1734th 1723/24 he served as rector of the university.
An invented by the German clockmaker and inventor Johann Bessler and Gera in the public imagined on June 6, 1712 wheel which allegedly turned without drive and then created a sensation, was inspected by ' s Gravensande to 1722 several times.
1720, he married Anna Savelaire, with whom he had two sons.
For practical demonstration of his doctrine designed ' s Gravensande a variety of equipment and instruments that have been realized by the instrument maker Jan van Musschenbroek, brother of physics professor Pieter van Musschenbroek.
The work 's Grave sand had a strong influence on the experimental physics of the eighteenth century. Some models of its instruments are located in the Institute and Museum of the History of Science in Florence.
Willem Jacob ' s Gravensande life taught at the University of Leiden. Invitations by Tsar Peter I at the Imperial Academy of Sciences of St Petersburg and of Frederick II of Prussia to the Berlin Academy he struck out.
An important contribution in mechanics was his experiment with two brass balls which he dropped on a smooth, soft surface of clay at different speeds. ' S Grave sand showed that, for example, is twice as fast falling ball causes four times as deep pit, three times as fast falling ball nine times creates a deep pit, and so on. He shared his findings with Émilie du Châtelet. Both were in correspondence with each other.
You Châtelet then corrected Newton's formula E = mv of the kinetic energy E α mv2 focus is E = mv for the kinetic energy E α mv 2 ( Later, a factor of 1/2 is added ) The concept of kinetic energy Émilie du Châtelet was from, based on considerations of Gottfried Wilhelm Leibniz, as Vis Viva, living force and the experiments introduced by ' s Gravensande. She represented exactly as Leibniz theorized that the kinetic energy must be proportional to v ². Isaac Newton, however, the view had represented, the kinetic energy is proportional to the velocity. She realized in the experiments of Willem Jacob ' s Gravensande confirming the ideas of Leibniz. Up to that time, was of the opinion of Newton, the kinetic energy is proportional to the velocity (see also acceleration).
Instruments
- Rolling up double cone
Writings
- Physices elementa mathematica, experimentis confirmata. 2 volumes (1720 /21)
- Philosophiae Newtonianae Institutiones, in usus academicos. (1723 )