LSS ACE ProjectIs Glass a Solid or Liquid?

Presented by:

Lee Liak Ghee 2i3 (10)

Introduction

IntroductionWhat 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

SolidsCrystalline molecular structure

Molecules vibrate about fixed positions

Heat increases vibrations

Melting pointmolecules start to flow

lose crystalline structure

Distinct phase transitionmelting/freezing involves heat of fusion

LiquidsViscosity: resistance to flow

e.g. water 0.01 poise; thick oil 1.0 poise

Cooling a liquid - increases viscosity

Below melting pointmolecules form crystals and solidify

Super-cooled liquid - remains liquid below freezing point

Depends on nucleation sites

What is Non-newtonian?

What is Glass made of?

What is Glass Made of?2 types:

Natural Glass and Man-made Glass

Natural GlassFormed when rocks melt

Lightning

Volcanic eruptions

Amorphous structure

High Silicon Dioxide(SiO2) capacity

Examples: Obsidian and Tektite

Natural GlassesObsidian Tektite

Man-made GlassMade of sand, soda ash & limestone

Heated to a high temperature

Cooled

Transparent, non-crystalline material formed

Who and How was Glass Discovered?

Who and How was Glass Discovered?

Natural glassIn use since the stone age

Man-made glassIn use as far back as 5000 years ago

Discovered by the ancient Egyptians

Molecular Structure of Glass

Molecular Structure of GlassAmorphous structure

Long chain of atoms

No crystalline structure

Characteristics of Glass

Characteristics of GlassAmorphous solid

Brittle

Transparent

Glass: Solid or Liquid?

How Glass is FormedSupercooled 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

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 ≥ 1013 poiseLiquid has viscosity < 1013 poise

Proof: Glass does not flowExcellent images of telescope lenses

Stone age arrow heads remain sharp

Excellent condition of 1st century A.D. Roman glassware

Stone Age Arrow Head

1st Century A.D. Roman Glassware

Conclusion

ConclusionFrom our viewpoint glass is solid

Scientific arguments are less conclusive

Non-newtonian Pool

Acknowledgementhttp://www.wisegeek.com/what-is-glass.htmhttp://www.glassonline.com/infoserv/history.htmlhttp://www.coleparmer.com/techinfo/techinfo.asp?htmlfile=Properties_Glass.htm&ID=608http://math.ucr.edu/home/baez/physics/General/Glass/glass.htmlhttp://abyss.uoregon.edu/~js/ast123/lectures/lec04.htmlhttp://www.google.com/imgres?imgurl=http://www.b14643.de/Tektites/Vredefort_1.jpg&imgrefurl=http://www.b14643.de/Tektites/index.htm&h=264&w=365&sz=16&tbnid=YXuCMoxBWuI06M:&tbnh=88&tbnw=121&prev=/images%3Fq%3Dnatural%2Bglasses&usg=__VrGWsbDtjM_owIIzwTP2wGCF3sU=&ei=wzXZS_PjOcOyrAeXtJTTDw&sa=X&oi=image_result&resnum=2&ct=image&ved=0CAgQ9QEwAQ

Acknowledgementhttp://wiki.answers.com/Q/Who_discovered_glasshttp://wiki.answers.com/Q/What_is_the_structure_of_glasshttp://en.wikipedia.org/wiki/Glasshttp://image.absoluteastronomy.com/images/encyclopediaimages/a/ar/arrowhead.jpghttp://www.youtube.com/watch?v=f2XQ97XHjVw&feature=relatedhttp://www.youtube.com/watch?v=gi-ITHJuTpQ&feature=relatedhttp://internationaltradecommodities.suite101.com/article.cfm/how_is_glass_made

The EndThank You