Archimedes (about 287 BC ~ 2 BC12 years) was a famous mathematician and physicist in ancient Greece. The founder of statics and hydrostatics. Born in 287 BC in the ancient city of Syracuse (now Syracuse, Italy) in Sicily, Mediterranean. His father was an ancient Greek astronomer and mathematician. Archimedes was deeply influenced by his father since childhood, preferring mathematics, and studied geometric principles with the famous Greek mathematician Euclid (about 330- 275 BC) very early. 1 1 years old, Archimedes went to Alexandria, a famous cultural center at that time. I have a strong interest in mathematics, mechanics and astronomy during my study. When he was studying astronomy, he invented a planetary instrument driven by water power, and used it to simulate the movement of the sun, planets and the moon and perform an eclipse of the sun and the moon. In order to solve the problem of irrigating land with Nile water, he invented a cylindrical spiral water lifter, which was later called "Archimedes spiral". In 240 BC, after finishing his studies, he returned to Syracuse and became a consultant to King Herod, helping him solve various scientific and technological problems in production practice, military technology and daily life. In 2 12 BC, the ancient city of Syracuse fell, and Archimedes, who devoted himself to scientific problems, was unfortunately killed by outrageous Roman soldiers.

Second, scientific achievements.

Archimedes' main scientific contributions are:

1. The lever law is systematically summarized and strictly proved, which lays the foundation for statics. Archimedes systematically studied the center of gravity and lever principle of an object on the basis of summarizing the previous experience, put forward a method to accurately determine the center of gravity of an object, and pointed out that if an object is supported at the center of gravity, it can keep the object in balance. In the book On the Balance of Plane Graphics, the center of gravity of various plane graphics is further determined, and the lever balance condition is strictly proved mathematically. It is concluded that the weight ratio of a heavy object is inversely proportional to its distance from the fulcrum. Using this law, Archimedes designed a lever pulley system, which created miracles such as pulling a big ship into the water with little force.

2. In the famous works about floating bodies, he summarized the famous Archimedes principle; An object placed in a liquid is subjected to upward buoyancy, which is equal to the gravity of the liquid displaced by the object. Since then, people have a scientific understanding of the ups and downs of objects, thus laying the foundation of hydrostatics.

3. Determine the calculation methods of the area of various geometric figures and the surface area and volume of objects, and establish an "exhaustive method". He is proficient in geometry and has discovered dozens of theorems. In the measurement of a circle, an accurate formula for calculating the circumference, area and sector area of a circle is put forward. In these calculations, he gradually approached the areas of inscribed polygons and circumscribed polygons by increasing the number of edges, and accurately found out the "exhaustive method" he created, which is essentially consistent with the basic idea of modern mathematical integral calculation. Archimedes further developed the "exhaustive method" when calculating the arc area of parabola and the surface area and volume of sphere, ellipsoid and rotating projectile in his works such as "On the quadrature method of parabola shape" and "On sphere and cylinder", which can be said to be the pioneer of modern calculus. He also pioneered the method of memorizing arbitrary large numbers, which broke through the limit that the number of Greek letters at that time could not exceed 10 thousand at most.

Compared with his predecessors and some contemporary scholars, Archimedes' academic activities have a remarkable feature, that is, he attaches great importance to the rigor and accuracy of science and requires accurate and logical proof of every problem; He also attached great importance to the practical application of scientific knowledge, personally designed and manufactured various mechanical devices and buildings, and created a style of study that closely combined theoretical research with practical application.

In addition to the above works, Archimedes' works have also been handed down, including Spiral, On Cone and Sphere, Calculation of Sand, etc. As far as we know, his lost works include Manufacture of Celestial Instruments, On Lever, Scaffold, Principle and Reflective Optics. Nearly two thousand years after his death, namely 1670, the complete works of Archimedes were published in Oxford, England. The works of Archimedes, which have been circulating for so many centuries, are all included in this complete collection.

Third, anecdotes

1. "Give me a fulcrum and I can move the earth."

It is said that when Archimedes devoted himself to the study of leverage, the king asked Archimedes, "Why does your research only stay in the game of learning?" What's the use of what you have learned? Archimedes replied heroically: "If you give me a fulcrum, I can move the earth!" " ""One sentence embodies a scientist's rich imagination, his profound understanding and fascination with the laws of mechanics, and Archimedes' unique wit and ideal. Of course, this fulcrum is hard to find, and Archimedes can't move the earth. But it is said that at that time, he designed a lever pulley system to easily push a huge ship into the water from the shore, which caused a sensation in his country. The king specially ordered: "Everything Archimedes said in the future must be obeyed."

2. "Crown logo"

Another important discovery of Archimedes in the field of mechanics is the law of buoyancy. Legend has it that Archimedes, with his rich experience and temporary inspiration, found a way to identify the true and false crown in the bath. It was 2,200 years ago, King Hai Rolle of ancient Syracuse asked a jeweler to make a pure gold crown for him. He was very happy when it was done, but he suspected that the craftsman had stolen his gold. There may be fakes in the crown, although the finished crown is as heavy as the gold sent. Who can guarantee that the crown is not made of silver? How to identify the crown without damage? The king handed the problem to Archimedes, who thought about it for many days, but there was no result. One day, he went to the bathhouse to take a bath. When he stepped into the bathtub, the water overflowed and he felt a little floating. Moreover, the more parts of his body are submerged in water, the more water overflows, and the greater the support of water to his body. Archimedes was ecstatic, jumped out of the bathtub and ran out naked, shouting "Eureka (Greek: found), Eureka" as he ran. Afterwards, he performed a program for the king and ministers: he put the crown, a piece of pure gold and a piece of pure silver with the same weight as the crown into a container filled with water, and measured their different volumes from the amount of water discharged. According to the fact that the crown is larger than pure gold and smaller than pure silver, he concluded that the crown was adulterated. Another way of saying it is that Archimedes took gold nuggets, silver nuggets and crowns with the same weight, weighed their gravity in the water respectively, and calculated their equivalent gravity in the water, which proved that the crown was indeed mixed with silver, and the craftsman was also punished by the king. Archimedes' "Eureka" shouted out the surprise when human beings explored the mysteries of nature. It is to commemorate this event that the most famous invention exposition in the modern world is named after "Eureka".

3. The Great Patriot

Archimedes was not only an outstanding scholar but also a great patriot. Legend has it that Roman general Maceiras led troops to attack Syracuse, and Archimedes and Syracuse people fought bravely against the invaders. He applied science to war and made many military inventions. He designed and built a large trebuchet. When the enemy arrived at the gate, as soon as he pressed the organ, the stone was automatically thrown and hit the enemy. He asked the people guarding the city to take a mirror, form a big concave mirror, focus the blazing sun on the oncoming enemy ships, and make the enemy cry. The Roman army was so afraid of Archimedes that Maceiras exclaimed, "This geometric monster" fooled us. His magic spells are many times more powerful than the legendary giant with 100 hands. "

4. "Kill my head in the future"

In 2 12 BC, the Roman army broke through the Yugoslav capital and entered Syracuse. Archimedes, 75, is still studying mathematics and proving his geometric problems. Roman soldiers shouted at the top of their lungs, which made him alert. "Hey, you stepped on my photo, go away!" Archimedes said angrily. The fierce soldier paid no attention and pointed his sword at his head. Archimedes understood what was going to happen and said calmly, "Kill my head later and let me prove this geometric theorem." However, the ignorant and cruel Roman soldiers cut off Archimedes' head with one knife.

5. Permanent commemoration

Archimedes' most proud discovery is that the volume of a cylinder with the same height and base diameter is equal to 1. 5 times the volume of the sphere inscribed with it. According to his instructions, people carved a cylindrical pattern with carved spheres on his tombstone as a permanent memorial.