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Published byMaud Thornton Modified over 9 years ago
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Presented by: Lee Liak Ghee 2i3 (10)
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Introduction
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What is solid? Fixed shape & volume Molecules closely packed, vibrates about fixed positions Strong intermolecular bonds What is liquid? Indefinite shape & fixed volume Molecules in clusters, slide over one another Weak intermolecular bonds
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Solids Crystalline molecular structure Molecules vibrate about fixed positions Heat increases vibrations Melting point molecules start to flow lose crystalline structure Distinct phase transition melting/freezing involves heat of fusion
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Liquids Viscosity: resistance to flow e.g. water 0.01 poise; thick oil 1.0 poise Cooling a liquid - increases viscosity Below melting point molecules form crystals and solidify Super-cooled liquid - remains liquid below freezing point Depends on nucleation sites
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What is Non-newtonian?
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What is Glass made of?
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What is Glass Made of? 2 types: Natural Glass and Man-made Glass Natural Glass Formed when rocks melt Lightning Volcanic eruptions Amorphous structure High Silicon Dioxide(SiO 2 ) capacity Examples: Obsidian and Tektite
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Natural Glasses ObsidianTektite
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Man-made Glass Made of sand, soda ash & limestone Heated to a high temperature Cooled Transparent, non-crystalline material formed
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Who and How was Glass Discovered?
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Natural glass In use since the stone age Man-made glass In use as far back as 5000 years ago Discovered by the ancient Egyptians
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Molecular Structure of Glass
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Amorphous structure Long chain of atoms No crystalline structure
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Characteristics of Glass
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Amorphous solid Brittle Transparent
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Glass: Solid or Liquid?
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How Glass is Formed Supercooled liquid cools further Molecules remain disordered Develops rigidity Becomes amorphous solid e.g. amorphous ice forms at -137 °C Glass is formed in this manner
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Glass is Liquid? Old glass panes thicker at the bottom than the top Some glass panes sagged Some have rippled surfaces Glass is a liquid with very high viscosity? Solid has viscosity ≥ 10 13 poise Liquid has viscosity < 10 13 poise
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Proof: Glass does not flow Excellent images of telescope lenses Stone age arrow heads remain sharp Excellent condition of 1 st century A.D. Roman glassware Stone Age Arrow Head 1 st Century A.D. Roman Glassware
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Conclusion
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From our viewpoint glass is solid Scientific arguments are less conclusive
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Non-newtonian Pool
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Acknowledgement http://www.wisegeek.com/what-is-glass.htm http://www.glassonline.com/infoserv/history.html http://www.coleparmer.com/techinfo/techinfo.asp?htmlfile=Proper ties_Glass.htm&ID=608 http://math.ucr.edu/home/baez/physics/General/Glass/glass.html http://abyss.uoregon.edu/~js/ast123/lectures/lec04.html http://www.google.com/imgres?imgurl=http://www.b14643.de/Tek tites/Vredefort_1.jpg&imgrefurl=http://www.b14643.de/Tektites/in dex.htm&h=264&w=365&sz=16&tbnid=YXuCMoxBWuI06M:&tbnh= 88&tbnw=121&prev=/images%3Fq%3Dnatural%2Bglasses&usg=__V rGWsbDtjM_owIIzwTP2wGCF3sU=&ei=wzXZS_PjOcOyrAeXtJTTDw& sa=X&oi=image_result&resnum=2&ct=image&ved=0CAgQ9QEwAQ
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Acknowledgement http://wiki.answers.com/Q/Who_discovered_glass http://wiki.answers.com/Q/What_is_the_structure_of_glass http://en.wikipedia.org/wiki/Glass http://image.absoluteastronomy.com/images/encyclopediaim ages/a/ar/arrowhead.jpg http://www.youtube.com/watch?v=f2XQ97XHjVw&feature=re lated http://www.youtube.com/watch?v=gi- ITHJuTpQ&feature=related http://internationaltradecommodities.suite101.com/article.cf m/how_is_glass_made
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The End
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