glass. composition properties history production

Glass

Composition Properties

History Production

What is Glass?• Glass is a state of matter, not a

substance.

• Glass combines some properties of crystals and some of liquids but is distinctly different from both.

• Glass has the mechanical rigidity of crystals, but the random disordered arrangement of molecules that characterizes liquids.

• Glass are usually formed by melting crystalline materials at very high temperatures. When the melt cools, the atoms are locked into a random (disordered) state before they can form into a perfect crystal arrangement.

What is in glass?• Silica (sand)• Anhydrous Boric Acid • Anhydrous Phosphoric Acid These

include: • Soda Ash • Potash • Lithium Carbonate • Limestone • Litharge • Alumina • Magnesia • Barium Carbonate • Strontium Carbonate • Zinc Oxide • Zirconia

Properties of GlassWhen created properly, glass can be:

Strong resists breaking when it has few surface imperfections & is cooled slowly

Hard surface resists scratches and abrasions.

Elastic gives under stress - up to a breaking point - but rebounds exactly to its original shape.

Chemical Corrosion-Resistant

Thermal Shock- Resistant

Heat-Absorbent

Optical Properties

Electrical Insulating

The History of Glass

– When it was discovered– How it was discovered– Where it was discovered– What its first uses were

Discovery

• Natural glass, obsidian, is formed by volcanoes and has been used since the stone age for tools

• Glass was discovered by accident as part of the copper smelting process in 1000 b.c. in Phoenicia (modern day Lebanon)

• Glass was first used as beads in jewelry

Ancient Glass vs. Modern Glass

The chemical composition

of glass has not changed much

since ancient times

In Ancient Rome…

Glass was so precious, the emperor Nero paid $500 dollars for one goblet!

The Island of Murano, Italy

• During 13th century Venice became the center of glassblowing. For safety, and to keep the process secret, the furnaces were moved to the Island of Murano, off the coast of Venice

Millefiori – A thousand Flowers

Renaissance to Modern Day

• Glassblowing was a dying Art. Mechanized processes overtook the hand-blown quality of the art

• During the 1960’s there was a rebirth of the Art Glass movement.

• Art Glass is increasingly popular since that time.

Dale Chihulya modern master

“Teamwork suits me.

This is the way artists like Michelangelo worked.”

Dale Chihuly

Venetian Vases

• With the assistance of Lino TagliapietraUnited States, Seattle, Washington, 1988Blown and hot-workedH (tallest) 44.9 cm89.4.9

Learning to Blow Glass

• A glassblower is also called a “gaffer”

Materials

• Glass “cullet” is melted in the furnace

• Frit – different shapes and colors of glass added for interest, color and texture

Tools

• The “punti” a long steel rod used to manipulate the glass

• The “blow pipe” used to actually blow the glass

• Molds – used for shaping the glass

The Finished Products

Where can I go to learn to blow glass?

• Belle Meade Hot Glass – Belle Meade, NJ

• Hot Soup – Philadelphia, PA

• Corning Glass Museum – Corning, NY

• Glassblowing.com – Poughkeepsie, NY

Resources

http://www.historyforkids.org/learn/science/glass.htm

http://www.eastfallsglass.com/

http://glassevolution.com/index.php

http://www.museum.state.il.us/exhibits/barker/gallery/index.php?RollID=group01&FrameID=Ac164273closmille

http://www.cmog.org/

www.chihuly.com

The End