GLASS

History of glass, its properties and its uses.

by Sarah Ang

History and Properties of Glass

• Glass is formed naturally when sand shoots out of a volcano and is heated until it melts.

• Natural glass has existed since ancient times. An example of natural glass is obsidian. You can find it in the Grecian islands, and ancient people (since the Stone Age) used to sail there just to get obsidian.

• Around 1000BC, people made glass beads by melting sand over a fire.

• Properties of glass – it is transparent, it is breakable, and does not conduct electricity. It is also a good insulator of heat. It can also be coloured by adding dyes.

Murano glass blowing in Venice, Italy. (http://farm3.static.flickr.com/2376/2238520233_b0d922ba72.jpg )

Murano glass sculpture. (http://www.visualsbysheree.com/Glasshorse.JPG )

Uses of glass

• In 700BC, the Phoenicians already made perfume bottles out of glass. Glass was also blown into shapes to make cups, vases, bottles and urns in the Roman empire ( 100BC)

• Glass was also used to make windows for houses, and stained glass windows decorated many churches in Europe.

• Glass is used in almost everything today, for example shower screens, TVs, spectacle lenses.

Blown glass bottles from the Medieval Ages (http://www.historyforkids.org/learn/science/glass.htm)

Sarah with sunglasses in Rome, Italy.

References: How glass is made (Alan Peterson, 1985).http://www.recyclingconsortium.org.uk/primary/facts/glass.htm

Q & A