null
What is pottery made from?

What is pottery made from?

Published by Excerpts from Wikipedia on 14th Aug 2015

  1. Pottery (from Wikipedia) is the ceramic material which makes up potterywares,[1] of which major types include earthenware, stoneware and porcelain. The place where such wares are made is also called a pottery (plural "potteries"). Pottery also refers to the art or craft of a potter or the manufacture of pottery.[2][3] A dictionary definition is simply objects of fired clays.[4] The definition of pottery used by the American Society for Testing and Materials (ASTM) is "all fired ceramic wares that contain clay when formed, except technical, structural, and refractory products."[5]
  2. Pottery originated before the Neolithic period, with ceramic objects like the Gravettian culture Venus of Dolní Věstonice figurine discovered in the Czech Republic date back to 29,000–25,000 BC,[6] and pottery vessels that were discovered in Jiangxi, China, which date back to 20,000 BC.[7] Early Neolithic pottery have been found in places such as Jomon Japan (10,500 BC),[8] the Russian Far East (14,000 BC),[9] Sub-Saharan Africa and South America.
  3. Pottery is made by forming a clay body into objects of a required shape and heating them to high temperatures in a kiln which removes all the water from the clay, which induces reactions that lead to permanent changes including increasing their strength and hardening and setting their shape. A clay body can be decorated before or after firing. Prior to some shaping processes, clay must be prepared. Kneading helps to ensure an even moisture content throughout the body. Air trapped within the clay body needs to be removed. This is called de-airing and can be accomplished by a machine called a vacuum pug or manually by wedging. Wedging can also help produce an even moisture content. Once a clay body has been kneaded and de-aired or wedged, it is shaped by a variety of techniques. After shaping it is dried and then fired.
  4. Clay comes from the ground, usually in areas where streams or rivers once flowed. It is made from minerals, plant life, and animals—all the ingredients of soil. Over time, water pressure breaks up the remains of flora, fauna, and minerals, pulverizing them into fine particles.
  5. Clay minerals are typically formed over long periods of time by the gradual chemical weathering of rocks, usually silicate-bearing, by low concentrations of carbonic acid and other diluted solvents. These solvents, usually acidic, migrate through the weathering rock after leaching through upper weathered layers.
  6. Porcelain (from Wikipedia) is a ceramic material made by heating materials, generally including kaolin, in a kiln to temperatures between 1,200 and 1,400 °C (2,200 and 2,600 °F). The toughness, strength and translucence of porcelain, relative to other types of pottery, arises mainly from vitrification and the formation of the mineral mullite within the body at these high temperatures.
  7. Porcelain derives its present name from the old Italian porcellana (cowrie shell) because of its resemblance to the translucent surface of the shell.[1] Porcelain can informally be referred to as china or fine china in some English-speaking countries, as China was the birthplace of porcelain making.[2] Properties associated with porcelain include lowpermeability and elasticity; considerable strength, hardness, toughness, whiteness, translucency and resonance; and a high resistance to chemical attack and thermal shock.
  8. Porcelain has been described as being "completely vitrified, hard, impermeable (even before glazing), white or artificially coloured, translucent (except when of considerable thickness), and resonant." However, the term porcelain lacks a universal definition and has "been applied in a very unsystematic fashion to substances of diverse kinds which have only certain surface-qualities in common" [3]

Links will take you back to Wikipedia.