Sir Isaac Newton FRS (4 January 1643 – 31 March 1727 [OS: 25 December 1642 – 20 March 1727]) was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian who is perceived and considered by a substantial number of scholars and the general public as one of the most influential men in history. His 1687 publication of the Philosophiæ Naturalis Principia Mathematica (usually called the Principia) is considered to be among the most influential books in the history of science, laying the groundwork for most of classical mechanics. In this work, Newton described universal gravitation and the three laws of motion which dominated the scientific view of the physical universe for the next three centuries. Newton showed that the motions of objects on Earth and of celestial bodies are governed by the same set of natural laws by demonstrating the consistency between Kepler's laws of planetary motion and his theory of gravitation, thus removing the last doubts about heliocentrism and advancing the scientific revolution.
Newton also built the first practical reflecting telescope and developed a theory of colour based on the observation that a prism decomposes white light into the many colours that form the visible spectrum. He also formulated an empirical law of cooling and studied the speed of sound.
In mathematics, Newton shares the credit with Gottfried Leibniz for the development of the differential and integral calculus. He also demonstrated the generalised binomial theorem, developed the so-called "Newton's method" for approximating the zeroes of a function, and contributed to the study of power series.
Newton remains influential to scientists, as demonstrated by a 2005 survey of scientists and the general public in Britain's Royal Society asking who had the greater effect on the history of science, Newton or Albert Einstein. Newton was deemed to have made the greater overall contribution to science, although the two men were closer when it came to contributions to humanity.
Newton was also highly religious, though an unorthodox Christian, writing more on Biblical hermeneutics than the natural science he is remembered for today.
Kamis, 03 Desember 2009
Isaac Newton
Rabu, 02 Desember 2009
Gitar
Gitar adalah alat musik berdawai yang dimainkan dengan jari-jemari tangan atau sebuah plektrum. Bunyinya dihasilkan dari senar-senar yang bergetar.
Gitar bisa berupa gitar akustik atau listrik, atau gabungan keduanya.
Gitar akustik adalah jenis gitar dimana suara yang dihasilkan berasal dari getaran senar gitar yang dialirkan melalui sadel dan jembatan tempat pengikat senar ke dalam ruang suara. Suara di dalam ruang suara ini akan beresonansi terhadap kayu badan gitar. Jenis kayu akan mempengaruhi suara yang dihasilkan oleh gitar akustik.
Gitar listrik adalah sejenis gitar yang menggunakan beberapa pickup untuk mengubah bunyi atau getaran dari string gitar menjadi arus listrik yang akan dikuatkan kembali dengan menggunakan seperangkat amplifier dan loud speaker. Suara gitar listrik dihasilkan dari getaran senar gitar yang mengenai kumparan yang ada di body gitar yang biasa disebut "pick up". Terkadang sinyal yang keluar dari pickup diubah secara elektronik dengan gitar effect sebagai reverb ataupun distorsi.
Gitar listrik pertama digunakan oleh gitaris-gitaris jazz yang memakai amplifier hollow bodied untuk mendapatkan suara yang lebih besar. Gitar listrik yang pertama adalah gitar hollow bodied dengan pickup baja yang dibuat oleh pabrikan Rickenbacker di tahun 1931. Gitar listrik adalah instrumen kunci dalam perkembangan musik yang muncul sejak 1940, termasuk Chicago Blues, rock and roll dan blues rock 1962.
