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What else do you know about huygens?
Christiaan Huygens

Christiaan huygens (1April 62914—1July 8, 695), a Dutch physicist, astronomer and mathematician, was the discoverer of Titan. He also discovered the Orion Nebula and Saturn's rings. He also designed a pendulum clock to time.

Christiaan huygens (1629 ~ 1695) is a Dutch physicist, astronomer and mathematician. He was an important pioneer in physics between Galileo and Newton.

Huygens was born in The Hague on April 1629. His father is a minister, diplomat and poet, and he often interacts with scientists. Huygens was smart, diligent, witty and versatile since he was a child. At the age of 65,438+03, he made a lathe by himself and received direct guidance from Descartes, a famous figure at that time. His father affectionately called him "my Archimedes". At the age of 65,438+06, he entered Leiden University to study law and mathematics. Two years later, he transferred to Brayda University, where he obtained a doctorate in law of 65,438+0655. He began his important scientific career there. /kloc-visited Britain in 0/663 and became a member of the newly established Royal Society. 1666, he was an academician of the French Academy of Sciences established in Ren Gang at the invitation of Louis XIV. Huygens was sickly and devoted himself to science. He never married. He died in The Hague on July 8th, 1995.

Huygens was in a wealthy and relaxed family and social conditions, and was persecuted from religion freely. He is good at combining scientific practice with theoretical research, thoroughly solving some important problems, and forming a working method combining theory with experiment and a clear physical thought. He left people with 68 kinds of scientific papers and works, including 22 volumes, and made great achievements in collision, pendulum, centrifugal force and fluctuation theory of light, optical instruments and so on.

His earliest achievement was mathematics. He studied the solution of envelope, quadratic curve and curve length. He discovered the difference between catenary cycloid and parabola. He is the founder of probability theory.

1668 ~ 1669, he is one of the winners of the royal society collision paper award. He studied in detail the problem of completely elastic collision (then called "collision on the center"). After his death, he published it comprehensively in On the Collision Motion of Objects (1703), including five hypotheses, 65438+.

Huygens studied pendulum and its theory from both practice and theory. 1656, he first introduced the pendulum into clocks and watches, replacing the gravity gear clock in the past. In Pendulum Clock (1658) and Geometric Proof of the Motion of Pendulum Clock or Clock Pendulum (1673), he put forward the famous simple pendulum period formula. The solution of complex pendulum and its vibration center is studied. Through the study of the evolute and the evolute, the isochron and cycloid are found. Three-line pendulum, conic pendulum, inverted pendulum and cycloidal clamp are studied. Figure 2-2-7 shows the appearance and internal structure of Huygens Ocean Clock, including pendulum, cycloidal splint and pawl unlocked by driving hammer every half a second.

Huygens discovered the center of gravity of the object system and Euler's later moment of inertia when studying the fluctuation of the center of gravity of the pendulum, and introduced the physical thought of "feedback", which is more meaningful today. He designed a hairspring for a marine watch, which greatly reduced the size of the watch. He also used pendulum to calculate the exact value of gravity acceleration, and suggested using the length of the second pendulum as the natural length standard. Huygens put forward his centrifugal force theorem. He also studied the circular motion, pendulum, centrifugal force when the object system rotates, and the oblateness when the mud ball and the earth rotate. These studies promoted the later establishment of the law of universal gravitation. He raised many interesting and enlightening questions about centrifugal force.

He designed and manufactured exquisite optical and astronomical instruments, such as grinding lenses and improving telescopes (Saturn's rings were discovered). ) and microscope, as well as Huygens eyepiece still in use today, as well as "Sky Telescope" (tubeless, long focal length, achromatic) and "Planetary Machine" that displays the starry sky (that is, the prototype of today's planetarium).

Huygens' letter to the Paris Academy of Sciences in 1678 and his book On Light published in 1690 all expounded his light wave principle, namely Huygens' principle. He believes that the particles of each luminophor transmit the pulse to the particles of the adjacent diffusion medium ("ether"), and each excited particle becomes the center of a spherical wavelet. Based on the elastic collision theory, he thinks that although such particles are independent, pulses propagating in all directions can be transmitted at the same time, so the beams cross each other without affecting each other. On this basis, the reflection and refraction of light are explained by graphics. The most wonderful part of On Light is the birefringence model, which explains the strange phenomena caused by ordinary light and extraordinary light by means of spherical and ellipsoid propagation. There are dozens of complex geometric figures in the book, which is enough to illustrate his mathematical skills.

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Dutch physicist, astronomer and mathematician. He and Newton are both scientists and one of the most famous physicists in history. He made outstanding contributions to the development of mechanics and the study of optics, and also made outstanding achievements in mathematics and astronomy. He is an important pioneer of modern natural science. He established the law of centripetal force, put forward the principle of conservation of momentum and improved the timer.

1April 629 14 was born in The Hague. My father is a priest and poet. He has close contacts with academic celebrities such as R Descartes. Huygens was clever from an early age. 13 years old, making lathes by himself, showing strong hands-on ability. 1645- 1647 studied law and mathematics at Leiden university, 1647- 1649 transferred to Brayda college for further study. Under the direct influence of Archimedes and Descartes, he devoted himself to the study of mechanics, optics, astronomy and mathematics. He is good at combining scientific practice with theoretical research to solve problems thoroughly, so he has made outstanding achievements in the invention of pendulum, the design of astronomical instruments, the collision of elastic bodies and the theory of light fluctuation. 1663 was hired as the first foreign member of the Royal Society, and 1666 was elected as an academician of the newly established Royal French Academy of Sciences. Huygens was sickly, devoted to science and never married. 1695 died in The Hague on July 8th.

Huygens first concentrated on studying mathematical problems. Huygens has an outstanding talent in mathematics. As early as the age of 22, he published books on calculating circles, elliptical arcs and hyperbolas. He has studied various plane curves such as catenary, drag line and logarithmic spiral, and has made achievements in probability theory and calculus.

On Calculation in Gambling, published in 1657, is a scientific paper on probability theory, which shows his accomplishments in mathematics. Starting from 165 1, some works on circles, quadratic curves, complex curves, catenary, probability problems and so on have been published. He also studied floating bodies and looked for the center of gravity of objects of various shapes.

Research and application of pendulum

The study of pendulum is the best physical work Huygens has done. For centuries, time measurement has been a difficult problem for human beings. At that time, timing devices such as sundials and hourglasses could not keep accurate in principle. It was not until Galileo discovered the synchronization of pendulum and Huygens applied pendulum to timer that mankind entered a new era of timing.

At that time, Huygens' interest focused on the observation of celestial bodies. In the experiment, he deeply realized the importance of accurate timing, so he devoted himself to the research of accurate timer. Galileo once proved that the simple pendulum motion is similar to the sliding motion of an object on a smooth slope, and the state of the motion is related to the position. Huygens further confirmed the isochronism of the vibration of a simple pendulum, and applied it to a timer to make the world's first chronograph pendulum clock. This pendulum clock is made up of gears of different sizes and shapes. It uses a heavy hammer as a pendulum. Because the pendulum can be adjusted, the timing is more accurate. In the book On Pendulum, Huygens introduced the making process of pendulum in detail, analyzed the swinging process and characteristics of pendulum, and introduced the concept of "swinging center" for the first time. He pointed out that when an object of arbitrary shape swings around the horizontal axis under the action of gravity, its mass can be regarded as concentrated at a certain point on the line between the suspension point and the center of gravity, thus simplifying the swing of complex objects into a simple pendulum motion to study.

Huygens also gave the basic proposition about the so-called "centrifugal force" in his pendulum theory. He proposed that an object moving in a circle tends to fly away from the center, and the centrifugal force it exerts on the center is directly proportional to the square of velocity and inversely proportional to the radius of motion. This is also his expansion of Galileo's swing theory.

When developing pendulum clock, Huygens further studied the movement of simple pendulum. He made the second pendulum (a simple pendulum with a period of 2 seconds) and deduced the motion formula of the simple pendulum. When the pendulum length was accurately taken as 3.0565 feet, he calculated that the acceleration of gravity was 9.8 m/s 2. This value is exactly the same as the value we are using now.

Later, Huygens and Hooke also discovered the isochronous oscillation of the spiral spring wire, which created conditions for the invention of modern hairspring pocket watches and watches.

Wave theory of light

In the long years of ancient and medieval times, light was a matter of great concern to philosophers and natural scientists.

/kloc-in the 0 th and 7 th centuries, scientists studied optical phenomena and laid the foundation of modern physics through excellent experimental work. There was a discussion about the nature of light during this period.

Huygens devoted himself to optical research while working in Paris. 1678, he publicly opposed Newton's theory of light particles in a speech at the French Academy of Sciences. He said that if light is a particle, it will change direction when it passes through. However, people did not find this phenomenon at that time, and using particle theory to explain refraction phenomenon will get contradictory results with reality. Therefore, Huygens formally put forward the theory of light fluctuation in the book On Light published in 1690, and established the famous Huygens principle. On the basis of this principle, he deduced the law of reflection and refraction of light, which satisfactorily explained the reason why the speed of light decreased in dense media, and also explained the birefringence phenomenon after light entered Iceland spar, which was thought to be caused by oval molecular particles of Iceland spar.

Huygens principle is an important basic theory of modern optics. But although it can predict the existence of light diffraction, it can't explain these phenomena, that is, it can determine the propagation direction of light waves, but it can't determine the amplitude of vibration propagating in different directions. Therefore, Huygens principle is an approximate understanding of optical phenomena by human beings. It was not until later that Fresnel developed and supplemented Huygens' optical theory and founded Huygens-Fresnel principle that the diffraction phenomenon was well explained and the whole theory of light wave theory was completed.

Huygens made a great contribution to astronomy. He devoted a lot of energy to developing and improving optical instruments. When Huygens was still in Holland, together with his brother, he successfully designed and ground the telescope lens with unprecedented accuracy, thus improving the Kepler telescope. Huygens made many astronomical observations with his own telescope. Therefore, his reward is to solve a long-standing astronomical mystery. Galileo once observed Saturn through a telescope. He found that "Saturn has ears", and later found that Saturn's "ears" disappeared. Scientists after Galileo have also studied this problem, but they have missed the point. "Saturn strange phenomenon" has become a mystery in astronomy. When Huygens aimed his improved telescope at the planet, he found a thin and flat ring beside Saturn, which was inclined to the orbital plane of the earth's revolution. Galileo discovered the disappearance of Saturn's ears because Saturn's rings sometimes look linear. Huygens later discovered Saturn's moon Titan, and also observed the Orion Nebula and the polar cap of Mars.

In the study of mechanics, Huygens is based on Galileo's creation. In the book about pendulum clock, the problem of collision is also discussed. About 1669, Huygens put forward a law to solve the collision problem-the conservation principle of "vitality", which became the pioneer of energy conservation. Huygens inherited Galileo's theory of simple pendulum vibration and made further research on it. He brought geometry into the field of mechanics and dealt with mechanical problems in an admirable way, which was fully affirmed by people.