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Created page with 'File:lighterstill.jpgright|frame ==Origin== [http://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Mid...'
[[File:lighterstill.jpg]][[File:Skull_Crucible.jpg|right|frame]]
==Origin==
[http://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English] ''corusible'', from Medieval Latin ''crucibulum'' earthen pot for melting metals
*[http://en.wikipedia.org/wiki/15th_century 15th Century]
==Definitions==
*1: a vessel of a very refractory material (as porcelain) used for melting and calcining a substance that requires a high degree of [[heat]]
*2: a severe test
*3: a place or situation in which [[concentrated]] [[forces]] [[interact]] to cause or [[influence]] [[change]] or development <conditioned by having grown up within the crucible of Chinatown — Tom Wolfe>
==Description==
A '''crucible''' is a container that can withstand very high [[temperatures]] and is used for metal, glass, and pigment production as well as a number of modern [[laboratory]] processes. While crucibles historically were usually made from [[clay]], they can be made from any material that withstands temperatures high enough to melt or otherwise alter its contents.
The form of the crucibles has varied through [[time]], with designs [[reflecting]] the [[process]] for which they are used, as well as regional variation.The crucible helps to prevent the [[heat]] from affecting the solution. The earliest crucible forms derive from the sixth/fifth millennium B.C. in Eastern Europe and Iran.
Crucibles and their covers are made of high temperature-resistant materials, usually [http://en.wikipedia.org/wiki/Porcelain porcelain] or an inert metal. One of the earliest uses of [http://en.wikipedia.org/wiki/Platinum platinum] was to make crucibles. Ceramics such as [http://en.wikipedia.org/wiki/Alumina alumina], [http://en.wikipedia.org/wiki/Zirconia zirconia], and especially [http://en.wikipedia.org/wiki/Magnesium_oxide magnesia] will tolerate the highest temperatures. More recently, metals such as [http://en.wikipedia.org/wiki/Nickel nickel] and zirconium have been used. The lids are typically loose-fitting to allow gases to escape during heating of a sample inside. Crucibles and their lids can come in high form and low form shapes and in various sizes, but rather small 10–15 ml size porcelain crucibles are commonly used for [http://en.wikipedia.org/wiki/Gravimetric_chemical_analysis gravimetric chemical analysis]. These small size crucibles and their covers made of porcelain are quite cheap when sold in quantity to [[laboratories]], and the crucibles are sometimes disposed of after use in precise quantitative chemical analysis. There is usually a large mark-up when they are sold individually in hobby shops.[http://en.wikipedia.org/wiki/Crucible]
[[Category: Chemistry]]
==Origin==
[http://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English] ''corusible'', from Medieval Latin ''crucibulum'' earthen pot for melting metals
*[http://en.wikipedia.org/wiki/15th_century 15th Century]
==Definitions==
*1: a vessel of a very refractory material (as porcelain) used for melting and calcining a substance that requires a high degree of [[heat]]
*2: a severe test
*3: a place or situation in which [[concentrated]] [[forces]] [[interact]] to cause or [[influence]] [[change]] or development <conditioned by having grown up within the crucible of Chinatown — Tom Wolfe>
==Description==
A '''crucible''' is a container that can withstand very high [[temperatures]] and is used for metal, glass, and pigment production as well as a number of modern [[laboratory]] processes. While crucibles historically were usually made from [[clay]], they can be made from any material that withstands temperatures high enough to melt or otherwise alter its contents.
The form of the crucibles has varied through [[time]], with designs [[reflecting]] the [[process]] for which they are used, as well as regional variation.The crucible helps to prevent the [[heat]] from affecting the solution. The earliest crucible forms derive from the sixth/fifth millennium B.C. in Eastern Europe and Iran.
Crucibles and their covers are made of high temperature-resistant materials, usually [http://en.wikipedia.org/wiki/Porcelain porcelain] or an inert metal. One of the earliest uses of [http://en.wikipedia.org/wiki/Platinum platinum] was to make crucibles. Ceramics such as [http://en.wikipedia.org/wiki/Alumina alumina], [http://en.wikipedia.org/wiki/Zirconia zirconia], and especially [http://en.wikipedia.org/wiki/Magnesium_oxide magnesia] will tolerate the highest temperatures. More recently, metals such as [http://en.wikipedia.org/wiki/Nickel nickel] and zirconium have been used. The lids are typically loose-fitting to allow gases to escape during heating of a sample inside. Crucibles and their lids can come in high form and low form shapes and in various sizes, but rather small 10–15 ml size porcelain crucibles are commonly used for [http://en.wikipedia.org/wiki/Gravimetric_chemical_analysis gravimetric chemical analysis]. These small size crucibles and their covers made of porcelain are quite cheap when sold in quantity to [[laboratories]], and the crucibles are sometimes disposed of after use in precise quantitative chemical analysis. There is usually a large mark-up when they are sold individually in hobby shops.[http://en.wikipedia.org/wiki/Crucible]
[[Category: Chemistry]]