Extractions: Online Encyclopedia Originally appearing in Volume V25, Page 293 of the 1911 Encyclopedia Britannica. Site Search - Over 40,000 encyclopedia articles. Encyclopedia Home SIV-SOU See also: SNELL , WILLEBRORD (1591-1626) , commonly known as SNELLIUS, Dutch astronomer and mathematician, was See also: born at See also: Leiden in 1591. In 1613 he succeeded his See also: father See also: Rudolph Snell (1546Â1613) as See also: professor of See also: mathematics in the university of Leiden. In 1615 he planned and carried into practice a new method of finding the dimensions of the See also: earth , by determining the distance of one point on its See also: surface from the parallel of another, by means of a triangulation. His
The World Communicates In 1621, the Dutch mathematician willebrord snell discovered the law of willebrord snell. Diffraction. Show source. Francesco Maria Grimaldi SJ http://science.uniserve.edu.au/school/curric/stage6/phys/communicates/History_se
Extractions: The World Communicates The story of communications and optics from the time of the ancients, now and into the future. Home Teacher Guide Student Guide History ... About this site The History of Communications and Optics Numbers in square brackets refer to the sources used to compile the following information. Ancient Cuneiform Sumerian cunieform script on a clay tablet Our story of communications starts around five and half thousand years ago (c.3500 BC) when the Sumerians invented cuneiform writing by making tool marks in clay tablets [ ]. These tablets were used to record everyday information about trade and commerce. Hieroglyphs Around 3000 BC, the Egyptians started using hieroglyphs to record all manner of things throughout their society [ ]. Today, we know so much about their life because so much of it was written down. Writing allowed ideas, plans and commerce to be shared among people in different places and across time. Example of Egyptian hieroglyphs: the funerary papyrus of Princess Entiu-ny First Postal Service Fire Beacons The inscriptions on bones and tortoise shells from Yin Dynasty ruins in Anyang of Henan province The earliest evidence of a postal service comes writing on a piece of bone dating back to the Shang dynasty in China (~1600 - 1100 BC) [ ]. The state used couriers on horseback to send important messages, such as military intelligence, across the country. In the Zhou and Qin dynasties (~1100 BC - 200BC), fires in beacon towers represented the first real use of optical telecommunications.
Refraction - Columbia Encyclopedia® Article About Refraction This law, credited to willebrord snell, states that the ratio of the sine of theangle of incidence, i, to the sine of the angle of refraction, r, http://columbia.thefreedictionary.com/refraction
Extractions: Feedback refraction, in physics, deflection of a wave on passing obliquely from one transparent medium into a second medium in which its speed is different, as the passage of a light ray from air into glass. Other forms of electromagnetic radiation electromagnetic radiation, energy radiated in the form of a wave as a result of the motion of electric charges. A moving charge gives rise to a magnetic field, and if the motion is changing (accelerated), then the magnetic field varies and in turn produces an electric field. These interacting electric and magnetic fields are at right angles to one another and also to the direction of propagation of the energy.
ScienceWeek 19 years before willebrord snell (1580 1626), who is usually given creditfor the details were worked out in 1621 by willebrord snell (1580-1626). http://scienceweek.com/2001/sw011012.htm
Stationary Paths In 1621, willebrord snell performed a series of careful measurements and foundthat when a ray of light passes through a surface at which the index of http://www.mathpages.com/rr/s3-04/3-04.htm
Extractions: The apparent bending of visual images of objects partially submersed in water was noted in antiquity, but it wasn't until Kepler's Dioptrice , published in 1611, that anyone attempted to actually quantify the effect. Kepler discovered that, at least for rays nearly perpendicular the surface, the ratio of the angles of incidence and refraction is (nearly) proportional to the ratio of what we now call the indices of refraction of the media. (Originally these indices were just empirically determined constants for each substance, but Newton later showed that for most transparent media the refractive index could be taken as unity plus a term proportional to the medium's density.) Incidentally, Kepler also noticed that with suitable materials and angles of incidence, the refracted angle can be made to exceed 90 degrees, resulting in total internal reflection, which is the basic principle of modern fiber optics. In 1621, Willebrord Snell performed a series of careful measurements and found that when a ray of light passes through a surface at which the index of refraction changes abruptly, the angles made by the incident and transmitted rays with the respective outward normals to the surface are related according to the simple formula (now called Snell's Law) where n and n are the indices of refraction (still regarded simply as empirical constants for any given medium) on the incident and transmitted sides of the boundary, and
Natur Des Lichts Translate this page snellius, willebrordus (willebrord snell van Roijen), geboren 1580 in Leiden.snellius war ein niederländischer Mathematiker und Physiker. http://www.mbaselt.de/licht/snellius.htm
À§´ëÇѼöÇÐÀÚ ¸ñ·Ï snell, willebrord van Roijen snell Born1580 in Leiden, Netherlands Died 30 Oct 1626 in Leiden, Netherlands http://www.mathnet.or.kr/API/?MIval=people_seek_great&init=S
Physics Of Continuous Matter snell, willebrord van Roijen (15801626). bullet. Stokes, George Gabriel (1819-1903).bullet. Strouhal, Vincez (1850-1922) http://www.nbi.dk/~lautrup/continuum/persons.html
Extractions: Some of these biographies are hard to find. The author is grateful for any suggestions that may improve this list. Almansi, Emilio (1869-1948) Archimedes of Syracuse (287-212bc) Avogadro, Lorenzo Romano Amadeo Carlo (1776-1856) Benard, Henri (1874-1939) ... Gauss, Johann Carl Friedrich (1777-1855) Glauert, Hermann (1892-1934) Goldstein, Sydney (1903-89) Grashof, Franz (1826-93) Green, George (1793-1841) Hagen, Gotthilf Heinrich Ludwig (1797-1884) ... Hubble, Edwin Powell (1889-1953) Hugoniot, Pierre (1851-87) Joukowsky, Nikolai Egorovich (1847-1921) Joule, James Prescott (1818-89) Karman, Theodore von (1881-1963) Kelvin, Lord (1824-1907) ... MacLaurin, Colin (1698-1746) Marangoni, Carlo (1840-1925) Millikan, Robert Andrews (1868-1953) Montgolfier, Joseph Michel (1740-1810) Montgolfier, Jacques Etienne (1745-99) Navier, Claude Louis Marie Henri (1785-1836) ... Newton, Sir Isaac (1643-1727)
NAHSTE: Excerpta Et Notanda In Kepleri ... Ad Vitellionem A discussion, probably inspired by Sir Isaac Newton, of whether it was WillebrordSnell or Voss who discovered a law of refraction first, from which Rene http://www.nahste.ac.uk/cgi-bin/view_isad.pl?id=GB-0237-David-Gregory-Dk-1-2-1-Q
Physics4all.co.il The summary for this Hebrew page contains characters that cannot be correctly displayed in this language/character set. http://www.physics4all.co.il/index.php?link=663
Extractions: SNELL van Roijen dit SNELLIUS, hollandais, 1581-1626 Huygens de Descartes Snell-Descartes (voire de Snell Il semble que l'on doive à Snellius (avant Neper n,d c m ... virgule Première loi de la réfraction : Si i et i / sin i est constant. Al Haytham (Alhazen) Huygens en donnera une preuve simple en posant comme principe la nature ondulatoire Kepler s'y intéressa mais ne découvrit pas cette loi des sinus. Principe de Fermat :
