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GLASS
- 2. TOPICS _history of glass _composition of glass _glass preparation _types of glass _glass recycling _usages of glass
- 3. GLASS Glass is a non-crystalline amorphous solid that is often transparent and has widespread practical, technological, and decorative usage in, for example, window panes, tableware, and optoelectronics
- 4. HISTORY OF GLASS ._First true glass was made in coastal north Syria _the story of glass dates back to ancient Egypt where glass-making became popular during the late bronze age. _Anglo-Saxon period glass was a luxury material across England. _in 10th century stained glass came to usage. _in 1330crwon glass was produced in rouen. _in 14th and 19th centuries stained glass employed in building purposes. _in 1843 henry bessemer invented float glass. _in 12th century reinfoorced glass and glass bricks came to usage.
- 6. SILICA(sand) _silica is another name for the chemical compound SILICON SiO2))OXIDE _each unit of silica includes one atom of silicon and two atom of oxygen _physical properties of silica are 1.Solid in room temperature 2.Pure silica is colorless but if contaminants are present in a sample of quartz, it may be colored 3.Silica has very high melting and boiling points(3,110F)(4,046F) _silica reacts with hydrofluoric acid, it also reacts with metal oxide like sodium oxide or lead oxide ,these reactions are used to produce different types of glass
- 7. SODIUM and CALCIUM OXIDE _sodium oxide is added to reduce the melting point of soda ash))the sand _calcium oxide is added to prevent glass from being limestone))soluble in water
- 8. MANUFACTURE OF GLASS •FUSION OF RAW MATERIALS Step 1 •WORKING WITH MOLTEN MASSStep 2 •ANNEALINGStep 3
- 9. AMOROHOUS GLASS _Glass is called an amorphous solid because its atoms are arranged in a random fashion. because of its irregular atomic structure , when glass is broken, it produces a variety of fracture patterns.
- 10. COLORED GLASS _colored glasses are due to inclusion of ions of chemical elements like: _iron(Fe) _cobalt(Co) _nickel(Ni) _copper(Cu) _chromium(Cr) _magnesium(Mg)
- 11. TYPES and USES Of GLASS _fused glass _borosilicate glass _soda-line glass _lead crystal glass
- 12. FUSED GLASS _the simplest type of glass is fused glass . it consists mainly of silica. _fused glass is made by heating silica to a molten liquid . the liquid is then cooled rapidly to form an amorphous solid.
- 13. SODA-LIME GLASS Soda-lime glass is the most common and earliest used glass. It is made by heating silica with calcium oxide and sodium carbonate at around 1 500 c and cooling it quickly
- 14. BOROSILICATE GLASS _When boron oxide B2O3 is added to soda-lime glass,borosilicate glass is formed. _it has a lower thermal expansion coefficient. _it is about 3 times as heat-resistant as soda-lime glass. _it is also more resistant to chemical.
- 15. LEAD CRYSTAL GLASS _lead crystal glass is soft and easy to melt _it is more expansive than soda-lime glass _it is used for the finest tableware,lead crystal glassware and art objects. _it is suitable for fine crystal becaouse it is optically transparent and contain much more lead.
- 16. RECYCLING GLASS