By Marshall Brain and Robert Lamb

http://www.howstuffworks.com

If you were to follow humanity's genetic trail back through the millennia, you'd find primitive creatures. Of course, Homo sapiens had one advantage over all the other animals: the ability to make and use tools. While they lacked a lion's teeth and claws or a deer's defensive antlers, they learned to craft their own weapons from the world around them. (294 no spaces)

The oldest known tools date back 2.6 million years, to a time when humans used shaped stone to carry out a variety of tasks. After all, a sharpened rock can potentially slice, stab, scrape, pound and bludgeon. In time, humans began to specialize their tools, creating everything from arrowheads to tools for grinding grain. Yet stone is a brittle, inflexible metter. Eventually, they were able to pinpoint more durable and malleable elements and their alloys: first copper, then bronze and iron. (415 no spaces)

If you had to name the technologies that had the greatest effect on modern society, the refining of the heavy metal element iron would have to be near the top. Iron makes up a huge array of modern products. especially carbon-rich, commercial iron, which we call steel. Cars, tractors, bridges, trains (and their rails), tools, skyscrapers, guns and ships all depend on iron and steel to make them strong. Iron is so important that primitive societies are measured by the point at which they learn how to refine it. This is where the "Iron Age" classification comes from. (473 no spaces)

Have you ever wondered how people refine iron and steel? In this article, you'll learn all about iron and steel. (93 no spaces)

The Advantages of Iron

Iron is an incredibly useful substance. It's less brittle than stone yet, compared to wood or copper, extremely strong. If properly heated, iron is also relatively easy to shape into various forms, as well as refine, using simple tools. And speaking of those tools, unlike wood, iron can handle high temperatures, allowing us to build everything from fire tongs to furnaces out of it. In contrast to most substances, you can also magnetize iron, making it useful in the creation of electric motors and generators. Finally, there certainly aren't any iron shortages to worry about. The Earth's crust is 5 percent iron, and in some areas, the element concentrates in ores that contain as much as 70 percent iron. (611 no spaces)

When you compare iron and steel with something like aluminum, you can see why it was so important historically. To refine aluminum, you need access to huge quantities of electricity. Furthermore, to shape aluminum, you have to either cast it or extrude it. Iron, however, is much easier to manipulate. The element has been useful to people for thousands of years, while aluminum really didn't exist in any meaningful way until the 20th century. (371 no spaces)

Fortunately, iron can be created relatively easily with tools that were available to primitive societies. There will likely come a day when humans become so technologically advanced that iron is completely replaced by aluminum, plastics and things like carbon and glass fibers. But right now, the economic equation gives inexpensive iron and steel a huge advantage over these much more expensive alternatives. (348 no spaces)

The only real problem with iron and steel is rust. Fortunately, you can control rust by painting, galvanizing, chrome plating or coating the iron with a sacrificial anode, which corrodes faster than the stronger metal. Think of this last option as hiring a bodyguard to take a bullet for the president. The more active metal has to almost completely corrode before the less active iron or steel begins the process. (345 no spaces)

Humans have come up with countless uses for iron, from carpentry tools and culinary equipment to complicated machinery and instruments of torture. Before iron can be put to any of these uses, however, it has to be mined from the ground. (196 no spaces)

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TASKS

1. Find in the text equivalents for the following:

крепкий, ковкий, прочный, щипцы для огня, плотнецкий инструмант, пытка, ржавчина

2. Match the words with their definition:

1) to slice

2) to scrape

3) to pound

4) to bludgeon

5) galvanizing

6) chrome plating

7) to corrode

a) разъедать

b) бить дубинкой, дубасить

c) скоблить

d) хромирование

e) нарезать

f) гальванизация

g) раздроблять

3. Answer the following questions: How do you think is creation of steel and iron important for our modern life? Explain you answer and give an example.

4. Remember the words from the text and give the synonyms of the following:

creation, to whet, fragile, to pierce, stiff