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Natural Science - Year I

Unit 14: Archimedes and Hero

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History Weblecture for Unit 14


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History Lecture for Unit 14: Hellenistic Machines

For Class

Lecture outline:

Simple Machines

In our unit on Theophrastus and Dioscordes, we introduced the idea of technology, using or directing scientific investigations and applying fundamental scientific concepts to practical situations. In this unit and the next, we will concentrate on technology in the ancient world, in particular, the specialization of engineering.

Engineering is the science of solving practical problems with machines. An engineer tries to identify all the criteria and requirements that must be solved, and then devises a complex machine built of simple machine components that address each issue to make a complete solution. Sometimes, this isn't as simple as breaking down a complex problem into parts and solving the parts separately, because the solution for one problem may prevent the solution of another problem, or even create new ones.

Modern engineers use complex computer models before undertaking the actual construction of buildings, cars, bridges, and space stations. These models take into consideration fundamental laws of physics, particularly mechanics and statics. But even without such technical help as computer models, the ancient engineers of Egypt and Mesopotamia were able to build enormous structures like the pyramids of Gaza and the ziggurats near Baghdad¹.

By 700 bce, the Greeks and Etruscans had learned and expanded upon the techniques of the Mesopotamian and Egyptian architects. Later the Romans added their administrative abilities to Etruscan engineering practices and built buildings, aquaducts, and roads that are still in use 2000 years later.

In this unit, we will look briefly at two areas of ancient engineering: the mechanical inventions of the Hellenist Greeks, Archimedes and Hero, and the building techniques of the Romans.

Ancient Engineers

Archimedes

The "father of mechanics" is the Greek Archimedes, who was born around 287 bce in Syracuse. Archimedes was famed in his lifetime as a mathematician; among his many mathematical accomplishments are the use of the method of exhaustion of Eudoxus, to determination the value of π as less than 22/7 (3.142857...) but more than 223/71 (3.14084507....). [The modern calculation of π to 10 decimal places is 3.1415926524.]

Archimedes was also a deviser of wonderous machines, including weapons, and the rulers of Syracuse retained Archimedes as an adviser in their struggle for independence against Rome. During the middle ages and the Renaissance, his works on mathematics and mechanics influenced engineers throughout Europe.

Please read about Archimedes at the University of St. Andrews' Mathematicians Site.

[Read 1 page; you may follow the linked information but it is not necessary].

    As you read, consider the following points:
  • What were Archimedes primary accomplishments in mathematics?
  • What were his accomplishments in mechanics (simple machines)?
Archimedes' Screw

Now let's look at one of Archimedes' useful inventions: the screw pump. This water pump was used throughout the ancient world, particularly in Egypt and Mesopotamia, for field irrigation and drainage, and its simplicity and ease of construction made it popular in the middle ages. In 1913, Albert Baldwin Wood built the first of 50 twelve-foot to fourteen-foot diameter screw pumps to allow the area around New Orleans to be drained. When power was restored to New Orleans after Hurrican Katrina in September of 2005, and the ninety-year old pumps cleared of debris, they were able to drain the city.

Please read about Archimedes' Screw at the Drexel University Archimedes Web Site. The first page contains descriptions from engineers and historians of the ancient world through the Renaissance. When you have studied these, click on the animations link at the top of the page and study the way the screw works.

[2 web pages]

    As you read, consider the following points:
  • What are two major applications for the screw that were used in the ancient world?
  • Is there a limit to how tall the screw can be?

Be sure to study the diagrams and manipulate the interactive animations so that you have a better sense for how this simple machine worked.

Hero

Several hundred years after Archimedes, the Hellenistic engineer Hero of Alexandria invented a number of mechanical devices, most of which were used as toys or scale models, and never actually built for practical work. His most famous invention was a kind of steam engine which used jet action to turn a sphere.

Please read about Hero of Alexandria from the translator's preface to his Pneumatics; then look over the different chapter titles and read Section 50, The Steam Engine.

[3 Web pages (counting the table of contents); one very short]

  • What are Hero's accomplishments?
  • How does his steam engine work?
  • Does it have any practical use?
  • When did Hero live, according to the translator's preface? What evidence does he give?

NOTE: This translation was made in 1851. Compare the dates for Hero's life cited in this Biography of Hero. Why do the authors of this article believe Hero lived around 62 CE?

¹ The Greeks and Etruscans were not alone in these accomplishments. The engineers of Mayan and Incan MesoAmerican tribes, and societies in China, Thailand, and on the Indian subcontinent also built pyramid structures that have survived to modern times. If you are interested, check out the "On Your Own" links below.

Now take a look at working models of some of Archimedes' and Hero's devices, as realized by modern Greek craftsmen.

Study/Discussion Questions:

Further Study/On Your Own