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Objective: ASWDTAT describe the properties of glass and ceramics. DO NOW . What are some ceramic and glass items that you have in your home? . Ceramics . Hard, crystalline solids made by heating clay and other mineral materials to high temperatures.
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Objective: ASWDTAT describe the properties of glass and ceramics. DO NOW What are some ceramic and glass items that you have in your home?
Ceramics • Hard, crystalline solids made by heating clay and other mineral materials to high temperatures. • Clay is made of water and very small mineral particles containing mostly silicon, aluminum, and oxygen. • Clay forms when the minerals in rocks break down.
Making Ceramics • When a clay object is heated above 1,000oC, much of the water present in the clay evaporates, and the particles of the clay stick together. • Natural ceramics have pores, tiny spaces that absorb and hold water. • Potters can coat the ceramic with a thin layer of silicon dioxide and heat it again.
Properties and uses for Ceramics. • Can break easily • Resist moisture • Do not conduct electricity • Can withstand temperatures that would cause metals to melt. Uses: store food, roofing tiles, bricks, sewer pipes, replacement body parts, in cars.
Glass • Sand mixed with limestone can be melted into a thick, hot liquid that flows like molasses. • If the liquid cools quickly, it forms a clear, solid material with no crystal structure, it forms glass.
Making Glass • Early glassmakers added calcium and sodium to the melting sand. • The mixture melts at a lower temperature than sand alone, so it is easier to work with. • Glassblowing: glassmakers put a blob of melted glass on the end of an iron pipe. By blowing air through the pipe, the glassmaker ends up with a hollow glass vessel.
Properties and Uses of Glass • Glass is brittle and can shatter when struck. • Clear, can be made in many shapes and colors, and can’t be penetrated by liquids. • Different materials can be added to glass to make it useful for particular purposes.
Communication through Glass • Optical Fiber: is a threadlike piece of glass that can be used for transmitting light. • When you talk into your phone, the signal created by your voice is converted to light signals and travel through the glass fiber. • They can put these lines under the ocean because they do not corrode and are easier to maintain.
