The story of invention 1
Newton-the discovery of gravity
Everyone knows the story that Newton discovered the law of gravity from the fall of an apple. In fact, it is just a story fabricated by Voltaire, a French enlightenment thinker, to promote natural science.
Before Newton, people knew that there were two kinds of "forces": all objects on the ground were affected by gravity, and there was gravity between the moon and the earth in the sky and between the planet and the sun. Are these two forces different in nature? Or are they different manifestations of the same force? Newton considered this problem when he was studying at Cambridge University.
When Newton was 23 years old, the plague was prevalent in London. In order to prevent students from being infected, Cambridge University informed students to leave school and go home to avoid the epidemic, and the school was temporarily closed. Newton returned to his hometown of Lincolnshire. He still hasn't stopped studying and thinking about gravity.
At that time, children in rural areas often used slings for several rounds and then threw stones far away. They can also pour a bucket of milk on their heads without spilling it.
This phenomenon inspired Newton's imagination about gravity: "What keeps the stones in the catapult and the milk in the bucket from falling?" This question reminds him of the ideas of Kepler and Galileo. He went from vast space, endless planets, cold moon to huge earth, and then thought about the interaction between these giants. This pair of Newton firmly grasped these magical ideas and plunged into the calculation and verification of "gravity". Newton plans to use this principle to verify the laws of the planets in the solar system. He first deduced the distance between the moon and the earth, but the calculation result was wrong because the quoted data was incorrect. Because it is assumed that the centripetal acceleration of the moon should be 16 feet per minute, but it is actually only 13.9 feet. In the predicament of failure, Newton did not lose heart, but made greater efforts to study hard.
167 1 year released the newly measured radius of the earth value. Newton used these data to re-examine his theory, and at the same time used his own calculus to deal with the calculation of gravity acceleration when the earth can not be regarded as a particle in the relationship between the moon and the earth. Through these two improvements, Newton got two identical acceleration values. This makes him feel that gravity and gravity are the same in essence. He also applied the three laws (Newton's three laws) based on the motion of objects on the ground to planetary motion, and reached a satisfactory and correct conclusion.
After seven years of cold and heat, Newton finally proved the world-famous "law of gravity" at the age of 30, laying the foundation for theoretical astronomy and celestial mechanics.
The discovery of the law of universal gravitation declared that everything in the sky and on the earth follows the same law, completely negating the different ideas of heaven and on the earth advocated by religious forces since Aristotle, which is a leap in the history of human cognition.
The Story of Invention II
With the development of radio technology, "clairvoyance" and "clairvoyance" have changed from fantasy to reality. The "clairvoyance" here refers to the radar invented in World War II. The radar sends out a pulse wave, which is reflected by the enemy and then received by the radar receiver, showing a bright spot on the radar screen. According to this bright spot, the azimuth, distance and altitude of the enemy plane can be calculated. Experienced observers can roughly judge what the target is from the bright spots. Using this method, we can find planes dozens or even thousands of kilometers away, which can of course be called "clairvoyance". But if you think about it carefully, "seeing" an airplane or a warship from the radio radar is nothing more than a bright spot on the screen, and it is puzzling for people who are not trained. Therefore, the radar detection distance can indeed reach thousands of miles away, and it is only an artistic exaggeration to say that it is an "eye".
After the laser appeared, the real "clairvoyance" was realized. Because of the short wavelength and concentrated direction of laser, imaging radar can be manufactured in principle. At that time, what you see from the screen will be the actual image of the target, not the bright spot. Of course, there are still many technical problems to be solved in building this imaging radar, so there is no such clairvoyance at present.
Some people may ask: Can a TV set be regarded as a clairvoyant? Generally speaking, TV can let you see cultural performances, football matches and so on. Thousands of miles away, this is also a clairvoyance. In fact, the "eyes" of TV relay equipment are TV camera tubes, which must be close to scenes and objects to have good results. The TV camera tube converts the captured image into radio waves and propagates in the air, and then it can be displayed on TV. If the distance between the two places is more than tens of kilometers, the microwave transfer station transmission system must be used. Strictly speaking, it's not clairvoyance.
Although the "Eye of the Sky" imaging radar can't be made for a while, a slightly inferior lidar has been made. Compared with microwave radar, it has many advantages: although both of them can measure distance and angle, laser radar has short wave length and thin beam, and its accuracy is more than 10 times higher than microwave radar. Lidar detects the ground from the height of 1500 meters, and the beam diameter is only 10 cm, which can distinguish the height change of the terrain, which is also impossible for microwave radar. Secondly, lidar is much lighter than microwave radar. In order to keep the same beam size at a certain distance, laser radar only needs a lens with a diameter of several centimeters, while microwave radar needs an antenna with a diameter of more than 60 meters. The antenna of long-range microwave radar has a large diameter and is usually fixed in the radar station. The whole lidar can be transported by truck, or even by a few people. Moreover, lidar can measure the speed and other parameters of the target, which is beyond the reach of general radar. Lidar also has good anti-jamming performance, which is not interfered by ground radio waves, which is a feature that the military attaches great importance to.
There are still some problems to be solved in the development of lidar, such as the influence of atmosphere on laser transmission and the difficulty of searching for targets caused by too thin beam. At present, two kinds of radars are often used together: microwave radar is used to search in a large range, and after the target coordinates are searched, laser radar is used to track the target in a small range to accurately determine the target coordinates and moving speed.
Lidar is widely used. In addition to military radar, non-military radar has been developed, which is not necessarily called radar. There is a kind of lidar called rangefinder, which can measure the distance from the moon to the earth. The absolute error is less than 15cm, and the relative error is less than 4× 10- 10. If an object with a length of 1 meter is measured with such high precision, the error is less than 4 hydrogen atoms. Linearity of hydrogen atom
The diameter of 10 is about 10 meter, that is, one tenth of a micron. Accurate measurement of the distance between the earth and the moon and its variation is very important for scientific research. Through this measurement, people can understand the shape and surface topography of the earth and the moon, thus measuring the gravity changes everywhere on the earth; In addition, by measuring the change of the distance between a fixed point on the earth and the moon, we can calculate the specific data of continental drift, and according to the change of the distance between the moon and the earth, we can also understand the relationship between the lunar gravity and the tidal changes on the earth. In addition, the laser rangefinder can also determine the position and orbit of satellites.
Lidar is very useful in space navigation. There is no air in space, and the laser beam will not be affected; The radar installed on spacecraft requires small size, light weight and low energy consumption, which is the specialty of lidar. A kind of lidar that can track spacecraft has been made, because of its high accuracy, which can make two spacecraft flying in orbit accurately dock and approach.
197 1 year, the Apollo spacecraft launched by the United States carried a "lunar rover" that could travel on the moon. The aircraft is equipped with lidar, which can directly control the TV camera to track the astronauts. After the astronaut's "roaming" was photographed by TV cameras, the signal was transmitted back to the ground through radio transmitting equipment. This kind of radar is very small and weighs only a few kilograms.
Because of the high beam resolution of lidar, it can not only identify behemoths such as tall buildings and mountains, but also find small targets such as telephone poles, chimneys and wires. Therefore, in the military, the anti-collision device made of lidar can be installed on fighters and helicopters flying at low altitude, which can prevent aircraft collision accidents.
Some lasers are very sensitive to changes in atmospheric composition. Scientists use this feature to invent pollution detection radar to detect air pollution.
All kinds of toxic and harmful substances produced by human production activities will be discharged to the outside world without treatment, which will do endless harm. For example, as long as the content of carbon monoxide in the atmosphere exceeds 100 thousand, big crops will not bear fruit. In order to detect these pollutants with very little content in time, monitoring instruments with particularly high sensitivity are needed.
Different pollutants can absorb different wavelengths of laser because of their different molecular structures. The latest laser pollution detection radar uses adjustable wavelength laser, which has high sensitivity and fast analysis speed. By changing the wavelength of laser and measuring the absorption, the composition and content of pollutants can be distinguished. More conveniently, the pollution detection radar carried on the vehicle can detect the air pollution within several kilometers around the vehicle's driving route.
The Story of Invention 3
On the skin of the end face of the last finger, there are concave and convex patterns, and the length, shape, thickness and structure vary from person to person, so the patterns formed therefrom have unique personality.
People's fingerprints are different, and this pattern will not change for life, so it has always been recognized that fingerprints can be used as the basis for solving crimes. Therefore, in some documents and contracts, fingerprints or signatures have the same effect. Public security organs can also pursue criminals according to their fingerprints. But the problem is that in many cases, the fingerprints left at the scene can't be seen with the naked eye or a magnifying glass. For example, fingerprints left on objects are soaked in water for a long time and hidden. What should I do? Then we need a laser to show it.
Why can laser make latent fingerprints show their true colors? It turns out that there are many sweat glands on the surface of human skin. When a person's finger touches the surface of an object, sweat secreted by sweat glands adheres to the surface of the object, forming a potential fingerprint. Under normal circumstances, the amount of fingerprints attached to objects is only about 0. 1 mg. Obviously, this is extremely trace, and in this 0. 1 mg sediment, water accounts for 99%, and they will evaporate quickly, leaving about half of inorganic matter and half of organic matter. Inorganic substances are mostly salts.
Because there are too few fingerprints left, some techniques are usually used to make fingerprints visible. However, if the time interval is too long, especially if the site is seriously damaged, coupled with the wind and rain, the conventional technical means will be powerless, because there are almost no traces of latent fingerprints.
At this time, if the object is irradiated with laser, a clear fingerprint can still be displayed. The latest research shows that even wood blocks, plastics, fabrics, glass and other things that have been soaked in water for 10 years can still show their fingerprints by laser irradiation after some necessary technical treatment.
With the increasingly sophisticated means of theft, anti-theft measures emerge one after another, and lock is a widely used anti-theft measure. The history of locks can be traced back thousands of years, but until the beginning of this century, locks were still relatively backward padlocks. The copper padlocks of these ingots are fastened with the shell only by two hollow copper pieces. Until the early 1960s, copper padlocks were widely used in rural areas of China.
Then came the pinball lock and the number lock. In recent years, some hotels have installed electronic locks, and passengers can open their doors and connect indoor lighting circuits by inserting magnetic cards into keyhole.
In some sci-fi movies, when someone wants to enter some top-secret rooms, they must stand at the door, put their eyes close to the inspection hole on the door, and then the door will open automatically. What does this mean? It turns out that people's fundus microvascular network, like people's fingerprints, varies from person to person, so the fundus microvascular network, also known as eye lines, can also be used as an ID card. Take a look at the eye pattern in the inspection hole on the door, and the computer inside can judge the identity of the visitor against the card, and then decide whether to open the door.
The so-called holographic lock is a practical laser anti-theft lock. Its principle is to record the fingerprints of all members of the owner's family on the negative by holographic method, and then store them in the holographic lock. To unlock the lock, first turn on the laser and let the laser beam irradiate the negative and the fingerprint on the finger respectively. If they match, the lock will open automatically. If it is a stranger's finger, the fingerprint will not match the one on the negative. Not only can the lock not be opened, but it will also call the police.
Holographic locks are especially suitable for security departments, such as archives, museums, banks, accounting offices and important warehouses.
The Story of Invention 4
The story of Edison
Edison is a world-famous inventor. When I was a child, because my family was poor, I only went to school for three months, and I started selling newspapers at the age of eleven or twelve. He loves science and often saves money to buy science books, newspapers and chemicals. The tools of his experiment are some bottles and cans picked out from the garbage.
When Edison 12 years old, he sold newspapers on the train. There is a special compartment on the train for passengers to smoke, and the conductor agrees that he will occupy a corner there. He moved chemicals and bottles there, sold out newspapers and did all kinds of interesting experiments.
Once, a bottle of white phosphorus was knocked down by a sudden vibration while the train was running. Phosphorus burns as soon as it meets air. Many people came to put out the fire with Edison. The conductor was so angry that he threw all Edison's experiments out and slapped him hard that he was deaf in one ear. Edison's determination to study science never wavered. He scrimped and saved, and started the chemical experiment again. On one occasion, sulfuric acid burned his clothes; On another occasion, nitric acid almost blinded his eyes. Undaunted by the danger, he still stubbornly did the experiment.
Edison tried to produce electric light. I don't know how many experiments he made before he found a filament with low price and long life. He often works in the laboratory for dozens of hours. He was so tired that he lay on the experimental platform and slept for a while. After such unremitting efforts, he finally found a suitable filament and invented the electric light. Later, Edison invented the film and the phonograph. . . He invented 1000 kinds of things in his life.
The Story of Invention 5
Watt invented the steam engine.
Watt (1736 ~ 18 19), a famous British inventor, was born in greenock, a small town near Glasgow, a British shipbuilding center. His father is a shipbuilding worker, and his grandfather and uncle are both mechanical workers. Influenced by his family, Watt has been familiar with many mechanical principles and manufacturing technologies since childhood.
Watt is a child with extraordinary wisdom. He is diligent, eager to explore and most interested in invention and creation. One day, my father's friend came to visit, just to see little Watt sitting by the fire in a daze, holding a pen and paper, and there were many paintings on the ground. He said kindly, "Little Watt should go to school. Don't just play at home to kill precious time. " Father smiled and said, "Thank you, my friend. However, you'd better see what my son is playing with ... "It turns out that Little Watt is designing all kinds of toys and drawing many patterns. This year, Little Watt just turned 6, and the guest said in surprise, "What a good boy!" "
On another occasion, the whole family went out, leaving only Watt as the doorman. He stared blankly at the teapot boiling water on the stove. The water is about to boil, and the lid of the pot is pushed up by steam, shaking up and down ... He thinks: This steam is really powerful. If you can make a bigger stove and use a big boiler to boil water, the steam generated will definitely be dozens or hundreds of times larger than this. Can't it replace a lot of manpower as the driving force of all kinds of machinery? This is the legendary story of "Watt invented the steam engine". Little Watt imagined it this way, but the steam engine was really trial-produced later.
In order to make inventions, Little Watt worked hard to learn scientific knowledge. /kloc-started studying geometry at the age of 0/3; /kloc-finished reading Principles of Physics at the age of 0/5; /kloc-started as an apprentice at the age of 0/7. From then on, he really devoted himself to the development and invention of the steam engine and never closed it.
1757 watt went to Glasgow university as a teaching instrument repairman. There are not only complete experimental facilities and various instruments here, but also many famous scholars and experts, which provide extremely favorable conditions for Watt. The school also set up an experimental workshop specially for him. 1769, based on a large number of experiments, Watt made a single-acting steam engine and obtained the patent right of the first steam engine after numerous failures. 1782, watt successfully developed a new type of two-way steam engine, which can be widely used in various machines. 1788, the British government officially granted Watt a patent certificate for manufacturing steam engines; From 1775 to 1800, Soho factory jointly operated by Watt and Bolton produced 183 steam engines, all of which were used in textile, metallurgical and mining industries. By the 1930s of 19, the steam engine was introduced to the whole world, and human society entered the "age of steam" from then on. Watt, the inventor who benefited mankind, will always be admired by future generations.
The Story of Invention consists of five related articles:
★ The latest five stories of invention
★ Collected 5 science stories.
★ Complete works of 5 stories
★ Fictional story 2020 episodes
★ Selected Invention Stories
★ Summary of selected invention stories
★ Selected five short stories of scientists
★ Selected five stories of China scientists.
★ Fictional Story Summary 2020
★ Invented Stories 2020 Collection