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What is Clay? Clay formation begins with the weathering of the earth's surface. The rock and stone that make up the earth's crust erode into microscopic particles to form clay. Because of this process, the chemical composition of clay resembles that of the igneous rock that makes up the earth's crust; the two major components are silicon dioxide and aluminum oxide Each clay particle is composed of sheetlike molecules or units, held loosely together, and they vary considerably in size. Basically, the chemical composition of clay is two molecules of water to two silicon dioxide molecules and one aluminum oxide molecule. In order for the clay to be transformed from a soft, malleable state into hard earthenware pottery, the water molecules need to be driven off.
The Introduction of Fire • Enter fire. Clay undergoes two basic stages in firing--dehydration and vitrification. After the excess water molecules have been transported to the surface of the piece of pottery by a process called capillary action and have been driven off by evaporation during the drying process, the pot may be fired. At about 3500 C, the molecular or chemical water, which cannot be removed by any amount of drying below that temperature, begins to be driven off. During dehydration, two molecules of water are driven off. The dehydration process is essentially complete at about 5000 BC. • Vitrification Process begins at 5000C melting impurities and crystals grow to interlock and make a rigid and bisgue structure. At this state pottery will no longer absorb water and will never return to it’s plastic state. • Ok enough science stuff….we now have clay.
The Earliest Ceramics came from Mesopotamia • Where is Mesopotamia? • Why was this area where we find the earliest known • civilization? • Between two rivers between mountain ranges • What we know today as IRAQ • What is civilization? • When there is order, govt., society, culture • language, monetary exchange of some kind
What do you need to Survive? • FOOD, WATER, AND SHELTER • Shells, skulls, nuts and scooped out fruit skins all must have been used to hold water or milk by our prehistoric ancestors. • With the need to transport items and food pre-historic man needed to use found containers and adapt to society’s needs. • Observation leads to invention.
Necessity is the mother of invention or so they say • Elephant tracks…..? Problem: High mortality rate for man. • Woman figured it out…. Natural items Solution: Clay holds water (elephants?) Gathering of small items and water in clay lined baskets made of woven reeds.
The Basket and the Pot In some communities basket making probably led to the technique of pottery making. How? The discovery that small lumps of clay could be squeezed and pressed into cup or bowl shapes and then put in a bonfire to make hard was an important stage in the life of most prehistoric communities.
Back to www.pottery.netfirms.comClay-lined BasketsWalk like an Egyptian!At some point, probably before 7000 B.C., someone discovered an easier, less wasteful, way to waterproof a basket - by smearing the inside with a layer of stiff mud or clay. Egyptians are credited with this discovery.
Tribal Wars and Domination • Serious fires destroying the huts, even villages of the conquered led to the discovery of ceramic pottery. Clay lined baskets became hard rot proof pots after baskets burned away. It would be a very valuable discovery. Back to www.pottery.netfirms.com
The Invention of Technology • Each generation brings something new to one’s culture. • Sometimes technology comes about in more than one place. Patents grew out of this concern to protect the inventor. • Sometimes an idea begins small and slowly evolves. Such as this little pot on this page.
Who were the first real potters? • Clay pots would have made carrying water and cooking a lot easier than using leather or woven containers What observations can you make from looking at this pot? What do you see?
Were the ancients satisfied with their new creation? • What might they have done next to improve upon the technology they had? Various Decorative Techniques and creating new and different pots to their individual taste. • Impressing, Stamping, Scratching, Painting and Staining
Pottery Techniques • The technique of pressing and coiling clay vessels and firing them in simple bonfires had probably spread throughout most of villages of Western Asia before 6500 BC. The pressed and scratched decoration was soon followed by brush painting with different clay slips, usually cream, brown, red, black or white. But human beings are generally slow to accept change; most of us like to keep the things we are used to.
Part of a collection of shards from this early period in Western Asia showing the brush strokes and incised marks imitating basket patterns. Notice the resemblance to baskets in the markings.
Pottery Today • Today texture and pattern play a critical role in the decoration of pottery.
Early Technology-The Potter’s Wheel • Most important advancement-for then and now. • 1st seen Mesopotamia in 3500BC…used for transportation. Used for manufacturing first. (Egyptians…1st to use spokes 2000BC…later developed in Europe 1400BC) • Did not develop in Western Hemisphere until after Europeans arrived.
