Archimedes (287 BC-2 BC12) was a great philosopher, mathematician and physicist in ancient Greece. Born in Syracuse, Sicily. Archimedes has been to Alexandria. It is said that when he lived in Alexandria, he invented the Archimedes spiral water lift, which is still used in Egypt. During the Second Punic War, Roman troops besieged Syracuse, and finally Archimedes died at the hands of Roman soldiers.

Scientific achievements

Archimedes invented a cross goniometer for astronomical measurement and made an instrument for measuring the angle between the sun and the earth. His most famous discovery is the principle of buoyancy and relative density, that is, the apparent weight of an object in a liquid is equal to the weight of the liquid, which was later known as Archimedes principle. In geometry, he created a method to find pi, that is, the relationship between the circumference and diameter of a circle. Meade famously said, "Give me a fulcrum, and I can move the earth." He devoted his life to the scientific research of volume and buoyancy. There is an interesting story. When the king asked the goldsmith to build a crown with pure gold, the king asked Archimedes to identify it because he suspected that the goldsmith had added sundries. Archimedes has been thinking about the method of identification. Just when he took a bath in the bathtub and saw the water overflowing, he realized the method of measuring the volume of irregular objects by buoyancy. He ran out of the bathroom in high spirits and shouted, "I found it!" " I forgot for a moment that I was naked. In addition, Archimedes also made mathematical achievements in geometry. Archimedes was the first engineer to talk about science. In his research, he used Euclid's method, assuming first, and then deducing the result with strict logic. He constantly searched for general principles and applied them to special projects. His works always combine mathematics and physics, so Archimedes became the father of physics. He applied the lever principle to the war, and his deeds of defending silas pigeons are widely known. He also used the same principle to derive the volumes of some spheres and bodies of revolution (ellipsoid, paraboloid of revolution, hyperboloid of revolution). In addition, he also discussed the related principles and achievements of archimedean spiral (such as the trajectory left by flies walking outward from the center of a turntable rotating at a constant speed), circle, ball and cylinder. Archimedes effectively used Euclid's approximation concept. He proposed that a circle circumscribes a polygon, and a similar circle circumscribes a polygon. When the number of sides is large enough, the perimeters of two polygons will approach the circumference of a circle from top to bottom. He used hexagons first, and then doubled the number of sides one by one until he reached 96 polygons. The estimated value of π is between 3. 14 163 and 3. 14286. In addition, he calculated that the surface area of the ball is four times that of the maximum inscribed circle. And he deduced that the volume of a sphere inscribed in a cylinder is two-thirds of that of a cylinder, and this theorem was engraved on his tombstone.

work

< methodology >

& lt on the floating body >

This book discusses the buoyancy of objects and studies the stability of rotating projectiles in fluids.

& lt about spheres and cylinders >:

Starting from several definitions and axioms, this book deduces more than 50 propositions about the area and volume of balls and cylinders.

& lt The balance of a plane figure or its center of gravity & gt；;

Based on several basic assumptions, this book demonstrates the principle of mechanics through strict geometric methods, and finds out the center of gravity of some plane figures.

& lt sand counter >;

This book is mainly about designing a method that can represent any large number.

& lt on the lever >

< On Split Conic Surfaces and Spheres >:

& lt parabola quadrature >

& lt on the spiral >