LECTURE 3.2LECTURE 3.2

LECTURE OUTLINELECTURE OUTLINE

Weekly ReadingWeekly ReadingPrototype Practice Quiz 3: FeedbackPrototype Practice Quiz 3: FeedbackFire: The Fourth ElementFire: The Fourth Element

CHAPTER V: THE CHALCOLITHIC AND BRONZE AGES

As the title implies, this chapter is concerned primarily with the processing of metals—in particular, gold, copper, and bronze. What is bronze? In its broadest sense, it is any alloy of copper other than the brasses, which are copper-zinc alloys. However, in this chapter, the only bronzes described in any detail are copper-tin and copper-arsenic alloys. The processing of these bronzes, together with gold and copper, is described against the backdrop of the Egyptian civilization in antiquity. The technology of the processing of metals is "told" through the eyes of Egyptian tomb painters.

In addition to the processing of metals, the production of Egyptian "faience" is described. Egyptian faience may be defined as a quartz (sand) figurine, which has a glassy surface layer (or glaze) that also serves to bind the quartz grains into a coherent whole.

CHAPTER V: THE CHALCOLITHIC AND BRONZE AGES

Finally, Chapter 5 finishes with a Materials' Essay: “A Quest for Strong Copper (Bronze).”

The essay is important for several reasons: It provides a rationale for the alloying of copper with elements

such as tin. It begs, but does not fully answer, the questions:

How were the original bronzes smelted?What particular event led to the incorporation of tin in copper?

CHAPTER VI: THE AGE OF IRON     We are all taught in high school that the Bronze Age preceded the Iron

Age, but never:Why did it take longer to "smelt" iron than it did copper and

bronze?Why is iron "more desirable" than bronze?What is the difference between wrought iron, cast iron, and steel?

These and other questions are answered in Chapter 6. The technology of the production of iron, in both the East and the West is described, and it is shown that the Chinese were able to melt iron over 2500 years earlier than the West.

CHAPTER VI. THE AGE OF IRON

Chapter 6 also introduces one Georgius Agricola, a sixteenth century German mineralogist and materials scientist who produced a remarkable compendium of the processing of materials in his book De Re Metallica, which loosely translates to "Concerning Mining and Metallurgy." The processing of iron circa A.D. 1550 is told through Agricola's prose, as translated by Herbert Clarke Hoover and his wife, Lou Henry Hoover.

Finally, the reader will meet Sir Henry Bessemer, whose invention of a cheap, efficient way of transforming pig iron into steel in 1856 ushered in the "Steel Age." The Bessemer Converter made possible such diverse construction projects as the Eiffel Tower in Paris, the Statue of Liberty (also designed by Gustave Eiffel) and the Reliance building in Chicago—the first of the downtown "skyscrapers."

CHAPTER VII: MONUMENTAL BUILDINGS IN ANTIQUITY

Part B closes with a highly selective account of the use of materials in "Monumental Architecture." The chapter opens with a discussion on the historical need for designing buildings that would only experience significant compressive stresses. This constraint is explained in terms of the materials that were available for "monumental building”—ceramics. The pros and cons of a post and beam method of construction, compared with the use of the arch, are presented.

Most of the Grecian architecture employed the post and beam, while the Romans made great advances in the use of the arch and its three-dimension cousin, the dome. Examples of Greek and Roman architecture are presented, and novel uses of materials such as wrought iron and concrete are discussed.

UNIT 3 PRACTICE QUIZ: UNIT 3 PRACTICE QUIZ: FEEDBACKFEEDBACK

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<Q2><Q2>The Ziggurats in Mesopotamia were constructed using The Ziggurats in Mesopotamia were constructed using ____.____.

<a><a> limestone blocks limestone blocks <b+><b+> fired bricks and bitumenfired bricks and bitumen <c><c> concrete concrete <d><d> marble and lime mortarmarble and lime mortar <e> <e> wattle and daubwattle and daub <F> The Ziggurats were constructed of brick because of the

paucity of masonry in Mesopotamia. Both clay and bitumen were in plentiful supply. Concrete was a much later invention and "Wattle and Daub" refers to a Medieval English method for building walls using a framework of wooden branches covered with mud, cow dung, and other unmentionable materials.

<Q4> Which of the following urban centers was famous for exporting obsidian in the Neolithic Age?

<a+> Catal Huyuk <b> Jericho <c> Troy <d> Harappa <e> Ur <F> The town of Catal Huyuk traded obsidian

throughout the Near East. Catal Huyuk is in modern-day Turkey (see answer to question 7).

<Q5> Applications of fire to the processing of materials during the Paleolithic Age included ____.

<a> smelting of copper <b+> tempering of arrowheads <c> smelting of bronze <d+> fire setting <e> smelting of steel <F> Both tempering of arrowheads and fire setting were Paleolithic

"inventions." Tempering was used to produce sharp and hard wooden points. Fire setting was used to shatter rock and was possibly the first stage in the production of many tools and/or weapons. The smelting of copper happened toward the end of the Neolithic Age or in the Chalcolithic Age. The smelting of iron was a much later development.

<Q6> The major changes to pottery that occur during firing are ______.

<a+> the clay like particles transform to silica and mullite <b+> the clay loses water of hydration <c+> the clay particles sinter to reduce porosity <d> the clay becomes transparent <e> the clay expands <F> The clay particles completely transform to "other

minerals" and the clay body sinters to a "monolithic" entity. The clay also loses water of hydration. The pottery may become shiny if it is burnished before firing.

<Q7> Figure 1 (next slide) is a schematic map of the Middle East. The location of modern-day Turkey is given by ____.

<a+> A <b> B <c> C <d> D <e> E <F> A

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Fire: The Fourth ElementFire: The Fourth Element

a

FIRE

a

BurnCookCalcine/FireCarbonizeMeltThermalShockTemperSmeltGlaze

a

may

a

To Adjust/ModerateTo PrepareFood for EatingTo “Bake”/Dry/OxidizeTo Fracture viaRapid TemperatureChangeTo Consume/Destroy To Convertto CarbonTo ConvertSolid to LiquidTo Produce aGlassy SurfaceTo ProduceMetal from Ore

a

isisis is is isis is is

a

PaleolithicNeolithicChalcolithic/BronzeIron

~ 10000BC~ 4500BC~ 1500BC

a

Agriculture(Slash and Burn)Weaponof WarForestClearanceHunting

a

Meat istenderized/preservedCereals/Crops arerendered edibleScavenging

Salt is extractedby boilingsalt-water

a

Yellow Ochreistransformedto Red OchreGypsum to “drywall/Limestone to lime.Used for e.g., plasterClay is“transformed”to pottery

a

Charcoal isused forSmeltingCharcoal isused forArtwork

a

Bitumen isused forWaterproofingGold/Silver arecastBronzes arecast

a

Flint ismined by“Fire Setting”Iron Ore ismined by“Fire Setting”

a

Flint istoughened

Steel istoughenedby temperingSteel isproducedby carburizing

Wood is“hardened”

a

Wrought Ironis smeltedCopper/Tin/Lead aresmelted fromtheir oresCast Ironis smelted

a

Faienze is createdby glazing quartzfigurenes andsoapstoneGlassis blownPottery Glazesare Developed