What law did Archimedes invent? Be specific! ! !

Archimedes (287 ~ 2 BC12) was an ancient Greek mathematician, scientist and inventor. He was born in Syracuse, a city-state in Sicily in 287 BC. His father, phidias, was an astronomer and related to the ancient Syrian king Henilo II. Archimedes was the founder of mechanical theory, at a time when society did not attach importance to mechanical invention. That this is not a real science, Archimedes made great contributions in this respect, making him famous all over the world. At the age of 1 1, Archimedes went to Alexandria, the Egyptian cultural center, to study and entered the mathematics school founded by Euclid. His teacher is a student of Euclid. Archimedes studied mathematics, astronomy, physics and so on there. He often stays in the museum for a few days, collecting all kinds of books. During his stay in Egypt, he invented the screw for carrying water. This is a long screw. It is placed in a cylinder. Put the bottom of the wooden screw in the water and the top on the shore. Shake the handle on the wooden screw and the water will be pumped up. This water-absorbing tool is called Archimedes spiral and is still used for irrigation in Egypt. It is used for drainage in the Dutch swamp area. Archimedes returned to Syracuse after studying in Alexandria and devoted himself to mathematical research. He didn't want to be a "mercenary maker of commercial and war machines like a beggar who was looked down upon", but in order to resist the Roman attack, he accepted the order of King Heinino and made many fighting machines. After the death of King Heinelo, the Romans finally sent troops to attack Syracuse. Roman general Maceiras led an army and a fleet to attack the city. Archimedes' genius was revealed in the war. It is said that his invention of stone cannons and iron tongs with wooden poles as big as bird's mouths dealt a heavy blow to the enemy. In 2 12 BC, Roman troops took advantage of the carnival in Syracuse to relax their vigilance and sneak into the city. Archimedes was solving a math problem at home at that time, and he was very absorbed. A Roman soldier forgot everything around him, broke into his house and trampled on Archimedes' drawings, which aroused the great indignation of the 75-year-old man. The savage invaders killed Archimedes with one knife. The Mystery of Crown and Archimedes Principle It is said that King Heinero made a golden crown. He suspected that the craftsman had stolen some gold with silver, and the king asked Archimedes to find out whether it was made of pure gold. You can't damage the crown. Archimedes held the crown in his hand and pondered all day. One day, Archimedes went to the bathroom to take a bath. He stepped into the bath tub, and when he was immersed in it, some water overflowed from the side of the tub. Archimedes saw this phenomenon and crackled in his mind. "I found it!" He forgot that he was naked, jumped out of the bath bucket and ran into the street, shouting "Youlega, Youlega!" " The spiritual happiness when discovering the truth is unimaginable to ordinary people. This cheer is the celebration bell of the birth of hydrostatics! Archimedes took a gold nugget and a silver nugget of equal mass and put them in a container full of water to see how much water was discharged. He found that although gold nuggets are as heavy as silver nuggets, silver nuggets discharge much more water. So Archimedes took a gold nugget with the same quality as the crown and put it in a container full of water to measure the amount of water discharged. Put the crown in a container filled with water and see if the water discharged is the same, and the problem will be solved. According to various historical records, we are not sure whether the craftsman is honest or not. This is not an essential problem, and we don't have to spend too much energy to pursue it, but an important physical principle has been deduced from this experiment. Archimedes put forward the concept of material density and made a liquid densimeter. He also wrote in "On Floating Bodies": The gravity reduced by an object immersed in water. It is equal to the gravity of the water it displaces. This is the famous Archimedes principle. I will be able to move the earth. Archimedes founded mechanics and discovered the working rules of levers, pulleys and screws. These machines can be used to move heavy objects, change the direction of force, or increase the speed of object movement. It is said that one day King Heinero was chatting with Archimedes, and Archimedes said, "Give me a place to stand, and I can move the earth." Heinello smiled and said, "Your statement is always reliable, because you can't prove it with facts." Archimedes was unconvinced and asked the king to find a heavy thing to carry by himself. The king chose a three-masted wooden boat and asked Archimedes to move it. Archimedes made full preparations, and on the scheduled day, there was a sea of people. Archimedes installed one on the dock. There is also a long screw with a handle, and many ropes and pulleys are connected to the screw from the ship. Archimedes unhurriedly shook the handle in front of the king, and a miracle appeared. Archimedes also asked the king to shake the handle himself, and the ship sailed forward obediently. The king immediately announced to everyone: listen, everyone, I order that from today on, no matter what Archimedes says, you must believe him. Archimedes was remembered on the tombstone. Archimedes discovered the relationship between the volume of a cylinder and the volume of its inscribed sphere before his death. He made a cylindrical cup with the same height and diameter, and a sphere that just fits into the cylinder. Archimedes filled the cylindrical cup with water, put the sphere in the cup, and the water overflowed from the cup. Comparing the volume of spilled water with the original water, he found that the volume of inscribed sphere is exactly two-thirds of the volume of cylinder. He was proud of this discovery and asked that it be engraved on the tombstone after his death.

Two thousand one hundred and ninety years ago, a great physicist appeared in Syracuse, Sicily, ancient Greece. His name is Archimedes (287-2 BC12 BC). Archimedes studied hard all his life, devoted himself wholeheartedly to science and was loyal to the motherland, and was respected and praised by people. Archimedes discovered the lever law and Archimedes principle named after him. And use these laws to design all kinds of machinery to serve the people and the motherland. The details of his life cannot be confirmed. But the story about his invention and defense of the motherland has been passed down to this day.

Establishment of lever law

People have used leverage since ancient times and know how to use it skillfully. When the pyramids were built in Egypt, slaves used levers to pry up heavy stones. The shipbuilder used a lever to erect a mast on the ship. People use shaduf to get water from wells and so on. But why can leverage do this? No one could explain the lever law before Archimedes discovered it. At that time, when talking about this issue, some philosophers insisted that it was "magic". Archimedes denied what "magic" it was. He knows that there are always natural reasons for all kinds of phenomena in nature. Lever also has its natural reasons, and he is determined to explain it. After repeated observation, experiment and calculation, Archimedes finally established the law of lever balance. That is, "the arm of force is inversely proportional to the force (weight)." In other words, it is: how many times is the small weight and how many times should the long arm be the short arm. After Archimedes established the lever law, he concluded that any heavy object can be lifted with little force as long as the appropriate lever length can be obtained. It is said that he once said such grandiloquence:

"Give me a fulcrum and I can lift the earth!"

King Syracuse heard this and said to Archimedes, "In the name of Zeus (Zeus is the king of gods in Greek mythology, in charge of heaven, thunder, electricity and rain), what you said is really strange, Archimedes!" After Archimedes explained the characteristics of lever to the king, the king said, "Where can I find a fulcrum to lift the earth?"

"There is no such fulcrum." Archimedes replied.

"So, it is impossible to convince people of the divine power of mechanics?" Said the king.

"No, no, you misunderstood, your majesty. I can give you other examples. " Archimedes said.

The king said, "You are too boastful! You can help me push the same heavy thing and see what you say. " At that time, the king had a problem, which was to build a very big ship for the king of Egypt. After the ship was built, the whole city of Syracuse was mobilized, and it was impossible to push it into the water. Archimedes said, "Well, I'll push the boat for you."

After Archimedes left the king, he used the principle of lever and pulley to design and manufacture a set of exquisite machinery. When everything was ready, Archimedes invited the king to watch the ship launch. He gave the end of a thick rope to the king to pull gently. Suddenly, the big ship moved slowly and slipped into the water smoothly. When the king and ministers saw such a miracle, they were as surprised as if they were watching magic! So the king persuaded Archimedes and issued a notice to the whole country: "From now on, no matter what Archimedes says, you must believe him ..."

The problem of weighing the crown

In the eyes of ordinary people, Archimedes is a "freak". In the words of Plutarch, a Roman historian, "He seems to be an enchanted man. He doesn't care about food or his body." Sometimes, the rice is put on the table and asked to eat, but he doesn't seem to hear it. He is still drawing his geometry in the ashes of the brazier. His wife should look after him at all times. For example, when he rubbed his body with oil, he just sat and oiled himself and forgot what he had done. His wife is more afraid of sending him to the bathhouse to take a bath. The joke was caused by a new crown of the king.

Not long ago, the king asked a craftsman to build him a golden crown. The king gave the craftsman the gold he needed. The craftsman's craft is very clever, and the crown produced is exquisite and unique, and the weight is as heavy as the gold given by the king at the beginning. However, someone reported to the king: "When making the crown, the craftsman swallowed some gold privately and mixed the same weight of silver." Hearing this, the king became suspicious, so he called Archimedes and asked him to try to determine whether the gold crown was mixed with silver and whether the craftsmen kept the gold for themselves. Archimedes was stumped this time. When he got home, he thought hard for a long time and couldn't find a way. I can't eat, sleep or take a shower every day, as if I were possessed.

One day, the king sent someone to urge him to report to the palace. His wife saw that he was too dirty and forced him to take a bath. When he was taking a bath in the bathhouse, he was still thinking about weighing the crown. Suddenly, he noticed that some water overflowed from the side of the bathtub when his body sank into it. At the same time, he felt that the deeper he went into the water, the lighter he was. So, he immediately jumped out of the bathtub, forgot to wear clothes and ran to the street of the crowd. He ran and shouted, "I found it, I found it, and the solution to the crown was found!" " "

After he entered the palace, he said to the king, "Please allow me to do an experiment, and then I can report the result to you." The king agreed. Archimedes put the gold, a piece of silver and the crown, which are as heavy as the crown, in the basin one by one, and saw that the gold nugget discharged less water than the silver nugget, while the crown discharged more water than the gold nugget.

Archimedes said to the king, "The crown is mixed with silver!" " "The king looked at the experiment and didn't understand. Let Archimedes explain. Archimedes said, "One kilogram of iron is bigger than one kilogram of wood. If you put them in water separately, the big wood will discharge more water than the small iron. I apply this principle to gold, silver and crowns. Because the density of gold is high and the density of silver is low, if gold and silver are equally heavy, the volume of silver must be greater than that of gold. Gold nuggets and silver nuggets with the same weight are put into water, and the amount of water discharged by gold nuggets is less than that of silver nuggets. The experiment just now shows that the crown discharges more water than the gold nugget, indicating that the density of the crown is smaller than that of the gold nugget, which proves that the crown is not made of pure gold. " Archimedes' methodical narration persuaded the king. The experimental results prove that the craftsman put the gold in his pocket.

This experiment of Archimedes is the embryonic form of "hydrostatics". However, he did not stop there and continued to study the floating body problem in depth. Results Archimedes principle, an important principle in natural science, was discovered. That is, when an object is immersed in a liquid, the volume of the displaced liquid is equal to the volume in which the object is immersed; Keep the buoyancy of the floating body equal to the weight of the liquid discharged by the floating body.

Miracles in the history of war

In 2 13 BC, the Roman army led by Marcailu invaded Archimedes' country Syracuse. At this time, Archimedes, who was 75 years old, immediately tried his best to help the motherland and fight against the enemy.

The commander-in-chief of Rome, Marcailu, became even more arrogant after successively capturing two cities in Syracuse. He believes that as long as it takes five days to prepare, the ancient city of Sila can be captured. But what he didn't expect was that Archimedes, a white-haired old man who loved the motherland, broke all his plans.

This battle 2 190 years ago was called a wonder in the history of war by historians!

Makaru led the fleet to attack Syracuse by water. The soldiers on each of his warships were equipped with bows and arrows, slings and light darts to drive the defenders of Syracuse out of the city, and then let the soldiers rush into Syracuse through the siege machines installed on the warships. However, Archimedes made full preparations. When the enemy's fleet approached, Archimedes started those huge long-range projectors he made. The long-range projector can project more than 200 kilograms of stones to a distance of 1000 meters (equivalent to the range of 18 th century artillery). These boulders hit the battleship like hail, which made Ma Kailu in a hurry and the ship sank to death, causing panic. Makaru had to evacuate the remaining warships in a hurry.

Makaru decided to attack again at night. He thinks Archimedes can't see the distance at night, and when the fleet reaches the gate, his huge long-range projection machine is unnecessary. However, when Makaru attacked at night, it was another disaster. Archimedes' short-range machines started, and these machines kept throwing short darts and stones, which caused the Roman army to suffer heavy losses again, and even Marcaille almost died.

Makaru was unwilling to give up his attempt to occupy Syracuse. He urged the army and forced his engineers to continue to compete with Archimedes. As a result, everything was in vain. Sometimes, when Rome rushed the warships equipped with siege machines to the gates of Syracuse, the city guards started a machine with a "long mouth", and pieces of stones fell from the "long mouth", which not only smashed the siege machines, but also smashed the warships, leaving Roman soldiers in a desperate situation. Sometimes, putting down an iron hook from the city is very flexible to be manipulated by the machine. The hook can hook the bow of a Roman warship and then pull it up, so that it can be overturned to one side and buckled into the water.

Mackailu tried all kinds of offensive means, which were all broken by Archimedes' invention. The Roman army became as timid as a mouse. As soon as they saw a rope sticking out of the wall, they ran away desperately and shouted, "Archimedes played tricks on us with another machine!" " "

Ma Kailu finally had no choice but to surround the ancient city of Silla in an attempt to trap the people in the city to death. In this way, Archimedes could do nothing. The Roman army has been besieged for eight months, and finally took advantage of the opportunity of celebrating festivals in ancient Syracuse and neglected to take precautions, and sneaked in through a remote gate before capturing Syracuse.

When the Roman army rushed into the city, Marcailu ordered not to kill the great physicist. But at that time, Archimedes was painting in his laboratory. Footsteps disturbed the soldier after he rushed in. The noise woke him up and shouted angrily, "Hello! You broke my picture, run quickly! " As a result, his indignation angered Roman soldiers and Archimedes died by the sword.

Although the great physicist Archimedes was killed, his contribution to mankind in science is immeasurable!