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Archimedes was diligent and studious all his life, devoted himself wholeheartedly to science and was loyal to his motherland, and was respected and praised by people. Archimedes discovered the law of lever and archimedes principle named after him. And use these laws to design a variety of machinery to serve the people and the motherland. The details of his life have been unable to be verified. But the story about his invention and defense of the motherland has spread to this day.

Establishment of the Law of Lever

People have used levers since ancient times and know how to use them skillfully. When the pyramids were built in Egypt, slaves used levers to pry heavy stones up. Shipbuilders use levers to erect masts on ships. People use shaduf to get water from wells, and so on. But why can leverage do this? Before Archimedes discovered the lever law, no one could explain it. At that time, when talking about this issue, some philosophers insisted that this was "magic". Archimedes did not admit what "magic" it was. He knows that there are always natural reasons to explain all kinds of phenomena in nature. Leverage also has its natural reasons, and he is determined to explain it. After repeated observation, experiment and calculation, Archimedes finally established the balance law of lever. That is, "the arm of force is inversely proportional to the force (weight)." In other words, that is: the small weight is how many times the weight of the large weight, and the long arm should be how many times the length of the short arm. After Archimedes established the lever law, he concluded that any weight 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 will lift the earth!" "

When King Syracuse heard this, he said to Archimedes, "By 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 magical power of mechanics?" Said the king.

"No, no, you misunderstood, Your Majesty. I can give you another example." Archimedes said.

The king said, "You are too boastful! You can push the same heavy thing for me and see what you say. " At that time, the king had a difficult problem, that is, he built 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 this boat for you."

after Archimedes left the king, he used the principle of lever and pulley to design and manufacture a set of ingenious machinery. After getting everything ready, Archimedes invited the king to watch the ship launch. He handed the end of a thick rope to the king for him 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 amazed as if watching magic! So, the king convinced Archimedes and issued a notice to the whole country: "From now on, no matter what Archimedes says, you should 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, and he doesn't care about food or his body." Sometimes, the rice is placed on the table to ask him to eat, but he doesn't seem to hear it. He still draws his geometric figures in the ashes of the brazier. His wife should watch over him at all times. For example, when he wiped his body with oil, he just sat and painted himself with oil, forgetting what he did. His wife was even more afraid of sending him to the bathhouse to take a bath. This joke was caused by a new crown of the king.

Not long ago, the king asked a craftsman to build a golden crown for him. The king gave the craftsman the amount of gold he needed. The craftsman's craft is very clever, and the crown made 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 the craftsman made the crown, he swallowed some gold privately and mixed the same weight of silver." After listening to this, the king became suspicious, so he called Archimedes and asked him to try to determine whether the gold crown was mixed with silver or not, and whether the craftsmen took the gold for themselves. This time, Archimedes was stumped. He went home and thought hard for a long time, but he didn't find a way. Every day, he couldn't eat, slept badly and didn't take a shower, as if he 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, the problem of weighing the crown was still on his mind. Suddenly, he noticed that when his body sank in the bathtub, some water overflowed from the side of the bathtub. 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. As he ran, he shouted, "I've got it, I've got it, and the solution to the crown has been found!" "

After he entered the palace, he said to the king, "Please allow me to do an experiment before 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 water discharged by the gold nugget was less than that discharged by the silver nugget, while the water discharged by the crown was more than that discharged by the gold nugget.

Archimedes said to the king, "The crown is mixed with silver!" The king looked at the experiment and didn't understand it. Let Archimedes explain it. Archimedes said: "Compared with one kilogram of iron, one kilogram of wood is bulky. If you put them into water separately, the large 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, the volume of silver must be greater than that of gold if gold and silver are equally heavy. When gold and silver nuggets with the same weight are put into water, 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 convinced the king. The experimental results proved that the craftsman pocketed the gold.

Archimedes' experiment is the embryo of "hydrostatics". But he didn't stop at this point and continued to study the problem of floating bodies 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 liquid displaced is equal to the volume in which the object is immersed; Maintain the buoyancy of the floating body, equal to the weight of the liquid displaced by the floating body.

A wonder in the history of war

In 213 BC, Roman troops 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 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 Syrah 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 2,19 years ago is called by historians as a wonder in the history of war!

Marcailu led the fleet and attacked Syracuse from the water. The soldiers on each of his warships are equipped with bows and arrows, slings and light darts, to drive the defenders of Syracuse down to the city, and then let the soldiers rush into Syracuse through the siege machine mounted on the warships. However, Archimedes made full preparations. When the enemy's fleet approached, Archimedes started those huge long-range projection machines he made. The long-range projection machine can project more than 2 kilograms of stones to a distance of more than 1, meters (equivalent to the range of artillery in the 18th century). These huge stones, like hail, hit the battleship, making Marcailu in a hurry, and the ship sank to death, causing panic. Marcailu had to evacuate the remaining warships in a hurry.

Marcailu decided to attack at night. He thought Archimedes couldn't see far at night, and his huge long-range projection machines wouldn't be needed when the fleet arrived at the gate. However, when Marcailu attacked at night, it was a disaster again. Archimedes' short-range machines started, and these machines kept throwing short darts and stones, which made the Roman army suffer a heavy blow again, and even Marcaille almost died.

Marcailu is 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, it was all in vain. Sometimes, when Rome rushed warships 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, an iron hook is put down from the city, which is very flexible to be manipulated by the machine. The iron hook can hook the bow of the Roman warship, and then pull it up, so that it can be overturned to one side and buckled into the water.

Marcailu 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 has used another machine to play tricks on us!" "

In the end, Marcailu had no choice but to surround the ancient city of Syrah in an attempt to trap the people in the city to death. In this way, Archimedes was powerless. The Roman army has been besieged for eight months, and finally took advantage of the opportunity of the ancient Syracuse to celebrate the festival and neglect to guard against it, and sneaked in from a lonely 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 drawing his pictures in his laboratory. After the soldier rushed in, the sound of footsteps disturbed him. This disturbance woke him up and shouted angrily, "Hello! You broke my picture, run away quickly! " As a result, his indignation angered Roman soldiers and Archimedes died by the sword.

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