It is unlikely that early forms of man were fully aware of the impact on our world that their simple use of tools from bones, rocks and branches would eventually have. Even so, rock was rock and wood was still wood, no matter what shape they formed it to or what they attached it to make weapons and early knives or cleavers.
There were times however when the nature of wood or rock could change, they would have seen this and most likely have been very alarmed. The fire from the sky may have struck a tree causing it to burn and turn black. They would certainly have found that food they found or killed smelt bad, or didn’t taste quite so good after a few days in the sun. They may even have noticed that fruit juices became strangely stimulating to drink and affected them physically.
These changes in the nature of substances that form matter of all kinds forms what we now call Chemistry. These fundamental alterations in the nature and structure of substances are known as chemical changes. Today, we readily make chemical changes that are generally with some benefit in mind. Some, alas, are not.
The first of these “controlled” changes occurred when man developed that ability to start and maintain fires. This was the “discovery of fire” as history labels it. From this point onwards, man would soon find that the texture and taste of food was enhanced by mixing it with fire for certain times, he would find that mud became extremely hard and that food inside mud would have an even different taste and texture to that mixed directly with fire. It would not be long before man was shaping mud and baking it hard to hold food and other items. Eventually, this would lead to ceramics and even primitive forms of glass.
These times are generally grouped into what we call the Stone Age, a time generally thought to be prior to 8000 BC when in the Middle East a revolutionary change was occurring. Man learned to domesticate animals and grow some of the foods they needed and so provide more stable and ample supplies required for the increasing populations. They began to develop permanent dwellings. For the first few thousand years stone was still the dominant tool in this “New Stone Age” or “Neolithic Period”. By 4000 BC, this development was spreading out from the Middle East to areas of Western Europe. It was about this time that a significant discovery was made, that of metal.
Early man came to find and use metal but it is almost certain that these early metals would have been shiney nuggets of yellow gold or the red copper. Maybe they would have been in the streams or in a hole dug for another reason. We can however, assume that their rarity prevented any real use until maybe someone discovered that the bluish green rocks he or she has surrounded a fire with the night before had left nuggets of this red malleable material behind. It wouldn’t have taken them long to realize that by heating certain types of rock they could obtain these metals. The first evidence of this discovery is thought to have been around 4000 BC, on the Sinai Peninsula, East of Egypt. Copper frying pans have been found in Egyptian tombs that has been dated 3200 BC.
By 2000 BC an alloy of Copper, produced (no doubt by accident at first) from the heating of copper and tin ores together was common enough to be used in weapons and armour. This metal gives its name to the Bronze Age, during which the Trojan Wars occurred.
By 1500 BC the Hittites had discovered how to extract iron from its ores, a process requiring significantly higher temperatures than for copper or tin. Letters from 1280 BC from a Hittite king to his viceroy in an iron rich mountain region, make definite references to iron production. Iron itself is not a strong metal but during production it would pick up carbon from the furnace in enough quantities to form steel, a more malleable and stronger metal that could be formed into stronger armour and sharper blades. So began the Iron Age. By 900 B.C. several empires were building based on the strength of their iron, but even now the Egyptians were already turning their hand to other forms of chemistry. There was a great interest in the preservation of human bodies after death using pigments and juices from the natural world.
According to one theory they word “Chemistry” is derived from the word “khemeia”, a derivative of the Greek word “khumos”, meaning juice of plant and so khemeia is thought to mean the art of extracting juices, these juices may also refer to extracting liquid metal from rock and so this word can also mean “the art of metallurgy”.
By 600 B.C. the Greeks were beginning to concern themselves not only with the technology of the day but where it came from and why some things happened the way they did. They were setting out to develop what we might call, the first chemical theories. The first of these documented, lies with the philosopher Thales (c. 640 – 546 B.C.) who lived in Miletus, a region east of Turkey. What he was asking himself was that if you can transform one substance into another that has no resemblance of the previous substance, what is the true nature of that substance? Is the true nature of the substance what is was in the beginning or what it was at the end? Maybe it was neither, maybe it was both. Moreover, was it possible to change any given substance into some other substance and so, are all substances just a different aspect of one basic material? The obvious answer to us now is a resounding YES, all substance can be converted into some other substances and more importantly, all substances are derived from one basic material.
At this time, the Greek philosophers knew very few pure and basic substances. Of these, Thales believed the basic substance, or element, was water. It may seem strange to think that rock can form from water but, Thales observed that water was present in the greatest amount, it surrounded the land, fell from the sky, permeated rocks and life was impossible without it. It was a logical choice. As with all good philosophy, his ideas were accepted by some, disputed by others and in 570 B.C. Anaximenes of Miletus concluded that the element was in fact air and that towards the center if the universe, then thought to be earth, air was compressed into harder and denser varieties such as water and earth. Heraclitus of Ephesus (c. 540 – 475 B.C.) took a different route and suggested that if change characterized the universe then the ever shifting and ever changing fire must be the element and that its fieriness made change inevitable.
During these times the scientific interest migrated westwards with the Ionians and about 529 B.C. Pythagoras of Samos (c. 582- c.497 B.C.) is thought to have travelled to Italy where his teachings are known to have been very influential. Empedocle of Sicily (c.490 – C.430 B.C.) asked, “Why does there have to be one single element?” and so developed the doctrine of four elements which was accepted by one of the best known of the Greek philosophers, Aristotle (384-322B.C.). Aristotle did not consider the elements as named, rather that they were combinations of opposites, hot and cold, dry and moist and he believed one property could not combine without the other. This he took further by proposing that each element had its own unique set of properties and also proposed a fifth element, ether (meaning “glow”) and applied this to the heavenly bodies as they were unchanged. Fifth Element, in Latin is “quinta essentia”, it is still used today to mark Aristotelian perfection in the word “quintessence” when we talk of something in its purest and most concentrated form.
During the debate over elements, another major question developed between the Greek Philosophers. They had observed that you could break down a rock into powder but how many times could you continue to make the subdivision. Leucippus of Ionia (c. 450 B.C.) maintained that eventually a piece so small would be obtained that it could no longer be subdivided. Democritus (c. 470 – c.380 B.C.) was a disciple of Leucippus continued to think about this and named the ultimately small particles “atoms” meaning “indivisible”. Democritus believed that the atoms of each element were distinct in size and shape and that it was this distinction that made the elements have different properties. Actual substances were mixtures of the atoms of different elements and one substance could be converted to another by changing the nature of the mixture.