The Golden Age
About 5,000 years ago, in 3,000 B.C., Egypt, one of the four ancient civilizations, was already established, and its capital, Cairo, was already a bustling town. It was bustling with people at market time. One day at noon, quiet and orderly town but there was a riot, people scrambling to a place, through the crowd around the dense, people found Cairo's famous traveler Risheer is holding a piece of yellow stuff, Risheer said that this is the God gave mankind's treasure, he called it gold. Soon the city of Cairo became rich in the possession of gold. People have to go looking for gold, the sand on the river bank stood full of people looking for gold, the beginning of only a few lucky to find pieces of gold, and then people noticed that the sand mixed with some sands, people have discovered the "Phi sand panning for gold" method. Later, people discovered the method of digging wells in the flat land to mine mountain gold, which made the gold production even bigger.
Shortly after Rithill discovered gold, he discovered silver. One cold night, Rithil and his companions talked around a campfire. The next day, just as they were about to depart, Richelle picks the fire, he is a careful traveler, every time before he leaves he always have to check the place where he lives so as not to have something lost, this time he not only did not find the lost things, the fire picks out some bright shiny things but attracted his attention, a great discovery accidentally came into being. Richelle found that this new metal and gold properties are very similar, also heavy and soft, with a pinch can make it deformed, he named this metal as silver. Later people followed this method that Rithill accidentally discovered, that is, using a campfire to burn the silver ore and get silver, which is actually a simple chemical reduction reaction, charcoal reduces the silver sulfide in the silver ore to silver.
Bronze Age
1939 is China's anti-Japanese war in the most difficult year, when an important discovery in the archaeological world was born in the war, in the village of Wuguan, Anyang City, unearthed a Yin Dynasty behemoth: Simuwu large square tripod. This big guy weighs 875 kilograms, need twelve strong adult men to lift up, visible at that time casting is not easy. The Simuwuding is the largest bronze vessel unearthed in the world. After testing, copper accounted for 84.11%, tin accounted for 11.64%, lead accounted for 2.79%. This bronze vessel is the product of the heyday of China's bronze smelting and casting, from its decoration, structure and so on reflect the high technology of bronze smelting and casting in this era.
The use of copper by human beings did not begin with bronze but with pure copper. Archaeologists have found small bronze devices, such as small needles, beads and cones, used before about 7,000 B.C. in some areas of western Iran. The British Museum has a collection of copper bull's heads cast by the Sumerians 5,000 years ago and copper mirrors and copper tools made by the Egyptians 3,500 years ago. In West Asia, where copper ore was bare on the surface, people burned charcoal fires on it to reduce the red copper, which was a different color from the green ore.
Because of the low hardness of pure copper, not very suitable for the production of tools, and later, people consciously in the refining of copper ore mixed with other ores, in order to make copper alloy to improve the hardness of the tools. In our country, the pre-qin ancient book "kao kong ji" recorded in the famous "six qi" rules, that is, is the bronze of the six formulas, this set of formulas provides for the different proportion of copper and tin caused by the different uses of bronze, in essence, is the proportion of different hardness. According to archaeological speculation, this time people have been able to make pure lead and pure tin. From the Shang Dynasty tombs have been found in the lead jerks, lead and lead dendrobium and other pure lead products.
Lead is a heavy metal, so lead and its compounds are poisonous, and the ancients began to suffer because they did not understand this. Ancient Romans used to like to use lead water pipes, archaeological discovery of ancient Romans often have black lead sulfide spots on the bones, which is due to the use of lead pipes in the water caused by chronic poisoning. Later, people gradually realized this, they no longer use lead utensils as eating utensils.
Tin because of its ductility and easy to make thin sheets, and at room temperature is not easy to oxidize, so since ancient times has been used to wrap utensils. China has unearthed several Yin Dynasty tiger copper helmet, one of them is very complete, the internal red copper is quite intact, the outside of a very thick layer of tin, tin layer is exquisite, is still bright as new. This shows that people at that time not only recognized that the tin layer is beautiful, but also can be anticorrosive. Pure tin has not been preserved, this is because tin is very afraid of cold, once the surrounding temperature is below 13 ℃ will undergo a phase change, into powdered gray tin, this phenomenon is known as the "tin epidemic".
Iron Age
Humanity's earliest knowledge of iron comes from the meteorite iron from space, the Egyptians called it "sky iron", some nomadic tribes in Western Asia, there is also an interesting legend, they say that since the iron is from the sky down, then the sky must be a large iron disk. Iron was found to be much harder than copper or bronze, and despite the legend that iron could only be found in the sky, there were some young men who did not follow their ancestral teachings and attempted to discover iron on earth. Around 2200 B.C., the Hittites in Western Asia were already smelting and using iron. In 1290 B.C., the king of Egypt wrote to the king of the Hittites to ask for some iron, and the king of the Hittites replied by promising to provide him with a steel sword but asking for gold in exchange, which shows that iron was still a precious metal at that time. The Hittite king also bragged in his letter, "In our land, iron is as plain as dust."
Early iron smelting technology also mostly used the solid reduction method, smelting, iron ore and charcoal stacked one layer at a time in the iron smelting furnace, ignited and burned to produce carbon monoxide, which reduces the iron oxide in the iron ore to a single iron. Early iron due to smelting temperature is very low and poor performance, is containing a large number of carbon and oxygen impurities in the alloy, the ancients called "bad gold". Our country in the early liberation of iron and steel, due to the local many "soil blast furnace" temperature does not go, and the production of a lot of worthless "bad gold". Later, people gradually found a way to raise the temperature of the furnace and refined a better performance of pig iron, and then invented the annealing method of "softening" pig iron and get low carbon steel. Later, people further invented cooked iron and steel smelting methods, iron in production from the widely used.
Mercury and Alchemy
Seven metals brought a new dawn to human civilization, but it was also these seven metals that plunged mankind into some kind of mysterious situation, and the ancient people were naive enough to believe that there were only these seven metals in the world. They believed that the metal originated from mercury (the common name for mercury) and sulfur, in fact, mercury is a silver-white liquid metal, similar in color and appearance to silver, copper, iron, tin and lead can be dissolved in mercury to form an alloy similar to gold and silver - amalgamation; mercury and sulfur will be generated after the combination of yellow mercury sulfide, similar to gold.
Based on these characteristics of mercury and metals, while people also recognize that mercury compounds are not gold and silver, alchemists believe that there should be a special way to make cheap metal copper, iron, tin and other metals into precious metals, gold and silver, they said that the transformation of the recipe is a thing called "philosopher's stone", but for thousands of years, the "philosopher's stone". "Philosopher's stone" is only a kind of alchemist's fantasy, no one has found this kind of thing. The Russian scholar Morozov wrote a poem entitled "The Seven Metals" to describe this idea of the alchemists, which is translated as follows:
The world is made of seven metals
The universe, she has given us
Copper, iron, silver, tin, lead, and gold
The father of the various metals is sulphur
Mercury is their mother
This kind of metal, which has been called "chemistry" in the history of science, is the "philosopher's stone", but for thousands of years the philosopher's stone was just a fantasy of the alchemists.
This kind of alchemy, which has been called the "germ of chemistry" in the history of science, has accumulated some information for the development of chemistry, but because they were far away from life and practice, and relied on logical reasoning, it led to the failure of this kind of scientific exploration. Until today in the 1990s, there are still a lot of people in our country who still have some naive fantasies about science, which gives some scientific charlatans a chance to succeed. The perpetual motion machine in the 1980s and the "water to oil" in the 1990s are obvious scientific frauds. From history to reality, it is well illustrated that science can not be based on fantasy, but can only be based on experiments under the guidance of the correct theory.