1.The First Materials (Stone Age and Copper-Stone Age) The names of some metals have entered certain linguistic us- ages.For example,the Greeks distinguished the Golden Age (dur- ing which supposedly peace and happiness prevailed)from the Silver Age.Rather than being descriptive of the materials that were used,these distinctions had more metaphorical meanings. Specifically,gold has always been held in high esteem in the eyes of mankind.Medals for outstanding performances (sport events, etc.)are conferred in gold,silver,or bronze.Specific wedding anniversaries are classified using gold,silver,and iron. Until very recently,the mastery of materials has been achieved mainly by empirical means or,at its best,by a form of alchemy. Only in the nineteenth and twentieth centuries did systematic re- search lead to an interdisciplinary field of study that was even- tually named materials science.This will be explained and demon- strated in detail in later chapters. Materials often have to be cut,shaped,or smoothed before they reach their final form and designation.For this,a tool that is harder than the work piece has to be set in action.As an exam- ple,flint stone having a sharp edge was used by early man for cutting and shaping other materials such as wood. The simplest and most common method of making stone tools from bulk rocks was by percussion flaking.Specifically,a lump stone was struck with another stone to detach small pieces from it.If these flakes happened to have sharp edges,they could be used as cutting tools.In early times,the tools were hand-held.Later (probably 5,000-10,000 years ago),stone flakes were attached to wooden handles using fibers or vegetable resin.This provided for better leverage,thereby amplifying their impact.Other flakes may have been used as spear or arrow tips,etc.(see Plate 1.1). Recent excavations in the Gona Valley of Ethiopia yielded about 3,000 tools consisting of hammer stones and knives prob- ably used to sharpen sticks or to cut meat.They are said to be two and a half million years old (!)and have likely been split from volcanic rocks.No remains of the toolmakers were found. Fishing hooks were made from shell and bone.Ground min- eral pigments were used for body painting.Grass fibers(e.g.,flax, hemp,etc.)or animal hair (wool)served as clothing and for hold- ing loose objects together.Jade,greenstone,and amber were uti- lized for adornments.This list could be continued. Stones,particularly flint and obsidian(a dark gray natural glass that precipitated from volcanic emissions,see Plate 1.2)were available to Neolithic man in sufficient quantities at certain lo- cations.Because of their abundance and their sharp edges,stones filled the needs as tools and weapons.Thus,it is not immediately evident why mankind gradually switched from a stone-using so- ciety to the metals age.The names of some metals have entered certain linguistic us￾ages. For example, the Greeks distinguished the Golden Age (dur￾ing which supposedly peace and happiness prevailed) from the Silver Age. Rather than being descriptive of the materials that were used, these distinctions had more metaphorical meanings. Specifically, gold has always been held in high esteem in the eyes of mankind. Medals for outstanding performances (sport events, etc.) are conferred in gold, silver, or bronze. Specific wedding anniversaries are classified using gold, silver, and iron. Until very recently, the mastery of materials has been achieved mainly by empirical means or, at its best, by a form of alchemy. Only in the nineteenth and twentieth centuries did systematic re￾search lead to an interdisciplinary field of study that was even￾tually named materials science. This will be explained and demon￾strated in detail in later chapters. Materials often have to be cut, shaped, or smoothed before they reach their final form and designation. For this, a tool that is harder than the work piece has to be set in action. As an exam￾ple, flint stone having a sharp edge was used by early man for cutting and shaping other materials such as wood. The simplest and most common method of making stone tools from bulk rocks was by percussion flaking. Specifically, a lump stone was struck with another stone to detach small pieces from it. If these flakes happened to have sharp edges, they could be used as cutting tools. In early times, the tools were hand-held. Later (probably 5,000–10,000 years ago), stone flakes were attached to wooden handles using fibers or vegetable resin. This provided for better leverage, thereby amplifying their impact. Other flakes may have been used as spear or arrow tips, etc. (see Plate 1.1). Recent excavations in the Gona Valley of Ethiopia yielded about 3,000 tools consisting of hammer stones and knives prob￾ably used to sharpen sticks or to cut meat. They are said to be two and a half million years old (!) and have likely been split from volcanic rocks. No remains of the toolmakers were found. Fishing hooks were made from shell and bone. Ground min￾eral pigments were used for body painting. Grass fibers (e.g., flax, hemp, etc.) or animal hair (wool) served as clothing and for hold￾ing loose objects together. Jade, greenstone, and amber were uti￾lized for adornments. This list could be continued. Stones, particularly flint and obsidian (a dark gray natural glass that precipitated from volcanic emissions, see Plate 1.2) were available to Neolithic man in sufficient quantities at certain lo￾cations. Because of their abundance and their sharp edges, stones filled the needs as tools and weapons. Thus, it is not immediately evident why mankind gradually switched from a stone-using so￾ciety to the metals age. 4 1 • The First Materials (Stone Age and Copper–Stone Age)