Great achievements ~ Three major contributions to optics
Before Newton, Mozi, Bacon, Da Vinci and others had studied optical phenomena. The law of reflection is one of the oldest laws of optics. At the time of the rise of modern science, Galileo discovered the \"new universe\" with his telescope, which shocked the world. The Dutch mathematician Snell first discovered the refraction law of light. Descartes proposed that the particles of light...
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Newton and his contemporaries Hooke and Huygens, like Galileo and Descartes, studied optics with great interest and enthusiasm. In 1666, while on sabbatical at home, Newton obtained the prism with which he carried out his famous dispersion experiments. When a beam of sunlight passes through a prism, it breaks down into spectral bands of several colors. Newton then uses a baffle with a slit to block the other colors of light. Only one color of light passes through the second prism, and the result is only the same color of light. In this way, he discovered that white light is composed of a variety of different colors of light, which is the first major contribution.
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In order to verify this discovery, Newton managed to synthesize several different monochromatic light into white light, and calculated the refractive index of different colors of light, which accurately explained the dispersion phenomenon. Uncovered the mystery of the color of matter, the original color of matter is caused by different colors of light on the object has different reflectance and refractive index. In 1672, Newton published his findings in the Philosophical Journal of the Royal Society, which was his first published paper.
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Many people study optics to improve refracting telescopes. Newton, because of his discovery of the composition of white light, believed that the dispersion phenomenon of refracting telescope lenses could not be eliminated (later someone eliminated the dispersion phenomenon with a lens composed of glass with different refractive indices), he designed and built a reflecting telescope.
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Newton was not only good at mathematical calculation, but also able to make various test equipment and do fine experiments by himself. In order to make the telescope, he designed his own grinding and polishing machine and experimented with various grinding materials. In 1668 AD, he made the first prototype reflecting telescope, which was the second major contribution. In 1671, Newton presented his improved reflecting telescope to the Royal Society, and Newton gained great fame and was elected a fellow of the Royal Society. The invention of the reflecting telescope laid the foundation for the modern large optical astronomical telescope.
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At the same time, Newton also carried out a large number of observation experiments and mathematical calculations, such as studying the abnormal refraction phenomenon of the glacier stone discovered by Huygens, the color phenomenon of the soap bubble discovered by Hooke, the optical phenomenon of the \"Newton ring\" and so on.
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Newton also proposed the \"corpuscular theory\" of light, which believed that light was formed by particles and took the fastest straight path. His \"corporeal theory\" and later Huygens' \"wave theory\" constitute the two basic theories of light. In addition, he also made a variety of optical instruments such as Newton's color disk.
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Newton's achievement
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Newton was the mastermind of classical mechanics. He systematically summarized the work of Galileo, Kepler and Huygens, and obtained the famous law of gravitation and Newton's three laws of motion.
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Before Newton, astronomy was the most prominent science. But why do planets have to go around the sun according to certain rules? Astronomers can't quite explain the problem. The discovery of gravitation shows that the motion of stars in the sky and the motion of objects on the ground are governed by the same law - the law of mechanics.
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Long before Newton discovered the law of gravitation, many scientists had seriously considered this problem. Kepler, for example, realized that there must be a force at work to keep the planets moving in elliptical orbits, which he thought was similar to magnetism, just as a magnet attracts iron. In 1659, Huygens discovered from his study of the motion of a pendulum that a centripetal force was needed to keep an object moving in a circular orbit. Hooke et al. thought it was gravity, and tried to extrapolate the relationship between gravity and distance.
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In 1664, Hooke discovered that comets' orbits bend as they approach the Sun as a result of the sun's gravity; In 1673, Huygens deduced the law of centripetal force; In 1679, Hooke and Halley deduced from the law of centripetal force and Kepler's third Law that gravity, which sustens planetary motion, is inversely proportional to the square of distances.
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Newton himself recalled that he had considered the problem of gravitation while living in his old home around 1666. One of the most famous stories is that Newton used to sit for a while in the garden during his holidays. Once, as had happened many times before, an apple fell from the tree...
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The accidental fall of an apple, however, was a turning point in the history of human thought, which opened the mind of the man sitting in the garden and caused him to think: what is it that causes all objects to be attracted almost always towards the center of the earth? Newton thought. Finally, he discovered the gravity that has epoch-making significance for mankind.
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Newton's genius was that he solved problems of mathematical argument that Hooke and others had not been able to solve. In 1679, Hooke had written to Newton to ask whether he could prove that planets move in elliptical orbits by the law of centripetal force and the law that gravity is inversely proportional to the square of the distance. Newton didn't answer the question. By the time Halley visited Newton in 1685, Newton had already discovered the law of universal gravitation: there is a force between two bodies, and the force is inversely proportional to the square of the distance, and proportional to the product of the masses of the two bodies.
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At that time, accurate data such as the radius of the Earth and the distance between the sun and the Earth were available for calculation. Newton proved to Halley that the gravity of the Earth is the centripetal force that moves the moon around the Earth, and that the motion of the planets under the gravitational pull of the sun complies with Kepler's three laws of motion.
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At the urging of Halley, at the end of 1686, Newton wrote a great landmark book, the Mathematical Principles of Natural philosophy. The Royal Society did not have enough money to produce the book, and it was only with Halley's support that one of the greatest works of science was published in 1687.
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In this book, Newton, starting from the basic concepts of mechanics (mass, momentum, inertia, force) and basic laws (the three laws of motion), and using the sharp mathematical tool he invented calculus, not only proved the law of universal gravitation mathematically, but also established classical mechanics as a complete and rigorous system, and unified the mechanics of celestial bodies and the mechanics of objects on the ground. Achieved the first big synthesis in the history of physics.
Isaac Newton was a great English mathematician, physicist, astronomer, and natural philosopher whose fields of study included physics, mathematics, astronomy, theology, natural philosophy, and alchemy. Newton's major contributions include the invention of calculus, the discovery of the law of gravitation and classical mechanics, the design and actual manufacture of the first reflecting telescope, and so on, known as the greatest and most influential scientist in human history. In honor of Newton's outstanding achievements in classical mechanics, the \"Newton\" later became a physical unit for measuring the magnitude of a force.