1. Presented by: Lee Liak Ghee 2i3 (10)

2. Introduction

3. 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

4. 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

5. 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

6. What is Non-newtonian?

7. What is Glass made of?

8. 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

9. Natural Glasses ObsidianTektite

10. Man-made Glass Made of sand, soda ash & limestone Heated to a high temperature Cooled Transparent, non-crystalline material formed

11. Who and How was Glass Discovered?

12. 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

13. Molecular Structure of Glass

14. Amorphous structure Long chain of atoms No crystalline structure

15. Characteristics of Glass

16. Amorphous solid Brittle Transparent

17. Glass: Solid or Liquid?

18. 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

19. 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

20. 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

21. Conclusion

22. From our viewpoint  glass is solid Scientific arguments are less conclusive

23. Non-newtonian Pool

24. 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

25. 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

26. The End