1888, the appearance of a faint Mars in a dark laboratory in Germany heralded the beginning of an unprecedented technological revolution. Heinrich hertz, a 3 1 year-old physicist, built a circuit in the laboratory. The circuit popped up a Mars in the corner of the laboratory, and then he looked at this Mars and caused another Mars to appear on the other side of the room. Hertz thus discovered the existence of electromagnetic waves. Electromagnetic waves can also travel at the speed of light in a vacuum-as predicted by Scottish physicist james clerk maxwell through mathematical operations 15 years ago, since then these electromagnetic waves have become the basis of today's global radio, television and electronic communication networks.
4. Eddington's experiment to confirm Einstein's theory of gravity (19 19).
1On October 7th, Einstein became the most famous modern scientist in the world. The global media reported the results of a scientific experiment, which showed that Einstein's theory of gravity-general relativity eliminated Newton's ancient law. According to the general theory of relativity, gravity is the result of space-time bending, which makes light bend when it passes near a mass object. Arthur Eddington, a British astrophysicist, decided to confirm this theory by measuring the influence of the sun's gravity on the light of stars near the sun during an eclipse in May 19 19. The bending effect predicted by Einstein's theory is twice that predicted by Newton's theory, but it is still very small: it is equivalent to the width of a hair seen from 14 meters away. After several months of analysis, Eddington announced that the small changes in the position of the star surface showed that Einstein's theory had defeated Newton's theory. Since then, more and more accurate measurements have confirmed Einstein's prediction.
Computer is one of the great inventions of human beings.
Throughout history, mankind has made countless inventions, one of which is the computer.
Computers can not only do various operations, but also make inferences and judgments. Because the computer has some functions of the human brain, it is called "computer".
Products invented in the past have relatively simple functions. For example, trains can only transport people and goods. The function of the computer is "alive". As long as it is given different programs, it can do different jobs and play different roles as needed. From industry and agriculture to music and movies, computers are everywhere. No other invention in the world has such a wide range of uses as computers.
With its fast operation speed and heavy workload, computers can accomplish many tasks that cannot be accomplished by human brain and manual labor.
The rapid development of the computer itself is also amazing. At present, the performance of personal computers is more than 654.38+ten thousand times that of the best computers in the early days. The highest performance of supercomputers has reached more than one trillion operations per second. In other words, the computer has been invented for 50 years, and its speed performance has improved by hundreds of millions of times. Aircraft invention 100 years, the performance has been improved by dozens of times; In 100 years, the performance of trains and cars has improved by less than 10 times.
The invention of laser realized the scientific and technological dream of mankind. Laser provides a very strong, very thin, very parallel and very pure monochromatic beam, which can evaporate hard and heat-resistant substances. For example, a small hole can be punched in the diamond as a metal wire drawing die; It can weld the retina that will fall off through the pupil of the eye and can be used in microsurgery. Laser originated in America. Einstein thought that 19 17 should have stimulated emission, but no one could find it. 195 1 one morning in spring, American physicist Challis? Sitting on a bench in the corner of Franklin Square in Washington, D.C., watching azaleas, Downs suddenly flashed a way to obtain high-purity electromagnetic waves from molecules. At this time, Downs is studying stimulated radiation. He remembered two new names: "pulse" and "laser". After three years of experiments, the maser he made successfully produced a very pure radiation cycle through the natural vibration of ammonia molecules. In the 1950s, the precision of the best timer in the world was 654.38+0.1 billionth of a second. Using an ammonia laser as the heart of an atomic clock, the precision was improved to 654.38+0 billionth of a second. 1957, Downs went back to study ultrashort waves. He found through experiments that the wavelength period of short infrared ray is almost 10000 times higher than that of microwave. 1958 65438+In February, Downs and Luo Xiao jointly published a paper to discuss practical laser problems, and began to trial-produce lasers. 1 In 960, Maiman, a physicist of Hughes Airlines, built the1practical laser.
4, the steam engine has a great historical role, it promoted the development of machinery industry and even society. The thermodynamics and mechanism established with its development laid the foundation for the development of steam turbines and internal combustion engines. Steam turbine inherits the characteristics of steam engine using steam as working medium, adopts condenser to reduce exhaust pressure, and abandons the shortcomings of reciprocating motion and intermittent steam intake; The internal combustion engine inherits the basic structure and transmission form of the steam engine, and forms a thermal cycle with much higher thermal efficiency by directly inputting fuel into the cylinder for combustion. At the same time, cylinders, pistons, flywheels, flying hammer governors, valves and seals used in steam engines are the basic components of many modern machines.
5. Satellites are widely used. Exploration satellites can measure topography, investigate surface resources and explore underground mineral deposits. Meteorological satellites can take cloud pictures and observe wind direction and speed; Spy satellites can collect military intelligence; Experimental satellites can help scientists do many experiments in space that cannot be done on the ground; Rescue satellites can search for distress signals sent by victims.
6. Penicillin is an antibiotic, a drug extracted from Penicillium culture solution, and the first antibiotic that can treat human diseases. At that time, the lives of thousands of wounded people were saved during World War II, and septicemia after injury was effectively prevented. For the first time, mankind has mastered the weapon against germs. Due to the discovery and mass production of penicillin, millions of patients with pneumonia, meningitis, abscess and septicemia have been saved, and many patients have been rescued in time. The appearance of penicillin caused a sensation in the world at that time. In recognition of this contribution to the benefit of mankind, Fleming, Ernst Boris Chane and Flory won the Nobel Prize in Medicine and Physiology in 1945 * *. The discovery and successful research of penicillin became a miracle in the history of medicine. Penicillin has developed into three generations since its clinical application.
7. Internet, that is, a wide area network, a local area network and an international computer network composed of a single computer according to a certain communication protocol. Internet refers to the result of connecting two or more computer terminals, clients and servers through computer information technology. People can email each other with friends thousands of miles away, finish a job together and have fun together. With the rapid development of knowledge economy, Internet has become a major theme in today's society. At present, the network is not only a symbol of fashion and trend, but also a concentrated expression of a country's overall scientific and technological level and even its comprehensive national strength.
Genetic engineering has become an indispensable part of biological science and the most fascinating science.
9. Test-tube baby is a baby developed by artificially fertilizing eggs and sperm in vitro, developing into early embryos and then transplanting them into the mother's uterus. Although some couples of childbearing age want children very much, they have been unable to do so for physical reasons. With the development of biological science and medical research, such couples finally have a remedy-they can hope for IVF technology and give birth to lovely dolls! Edwards, the father of IVF, won the 20 10 Nobel Prize in Physiology or Medicine. About 10% couples in the world suffer from infertility, which brings pain and trauma to these families. The curative effect of simple drug therapy on many infertility is very limited, but with the emergence of in vitro fertilization technology, all this has been solved. In vitro fertilization is a safe and effective method, and about 20% to 30% of fertilized eggs in vitro can eventually develop into fetuses. Follow-up research shows that there is no difference in health between children born in vitro fertilization and children born naturally.
10, electric light: the beginning of human conquest of darkness
The lamp is a great invention for human beings to conquer the night. 19th century ago, people used oil lamps and candles for lighting, which broke through the night, but still failed to completely liberate mankind from the restriction of the night. Only with the birth of the generator can we light up the world with all kinds of electric lights, turn night into day, expand the scope of human activities, win more time and create wealth for society.
1 1. Printing machine: accelerate the scale transfer of knowledge.
The oldest movable type printing originated in China, and printing is one of the four great inventions in China. However, this kind of printing only stays at the stage of hand carving, and it is difficult to complete large-scale printing tasks. The first printing press in the world was invented by German Johann Gutenberg in the 5th century. /kloc-in the middle of the 0/5th century, he brought the metal movable type casting method to Europe and printed the first movable type book in the western world. The invention of the printing press spread knowledge in a wider range and improved the education and knowledge level of the whole society.
12, telephone: making long-distance real-time communication a reality
The idea of long-distance love has long existed. In the 1970s, American inventor Gray first designed a "couple telegraph device". He has a perfect design theory, but it is not easy to turn it into reality. This arduous task fell to another inventor, Bell.
Bell was inspired by the telegraph device, and he finally turned Gray's idea into reality. And obtained the patent registration on February 1876. This invention was later called the telephone, but the original telephone was not like this. It requires us to shout so that the other side of the small city can hear it.
Cars: changed the mode of human transportation.
Since the automobile was born at the end of last century, it has experienced more than one hundred years of ups and downs. The first three-wheeled car made in karl benz has been running at the speed of 100km/h, and now a super sports car has been born, which only takes a little more than three seconds to accelerate from zero to 100km/h ... Excluding the impact on the environment for the time being, the invention of the car has expanded the living space of human beings, changed the mode of travel and made full use of human resources.
14, plane: the official flight of human beings.
190365438+February 17, this is a day in history. On this day, the Wright brothers in the United States achieved the first powered flight in human history. The flight time is only 12 seconds, and the flight distance is only a negligible 36 meters. But this is the first time in human history to successfully launch and fly a powered, manned, sustained, stable and maneuverable aircraft heavier than air, marking the beginning of the realization of human dreams of conquering the sky.
15, camera: really make the instance eternal.
An opaque box. This is a camera. A camera is a photographic equipment that uses photographic film to shoot a scene. Its invention took a long time. However, the invention of the camera is an epoch-making revolution in the mastery of light and shadow technology. Cameras allow people to preserve the past in a more intimate and vivid way, make history more vivid, and truly make the moment eternal.