Hitno prepricavanje !

Hitno prepricavanje !

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  • Ben123 
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  • Pridružio: 05 Okt 2010
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Napisano: 21 Okt 2010 14:49

Hitno prepricavanje ovog teksta :

The first materials that people used were stone ,wood and bones ,but around 4000 bc the first metal tools appeared.They were made of copper.We don't know how people discovered copper.It was probably when people put some rocks round a fire and the fire melted the metal in the the rocks.In fact,people had metal before that time.They already knew about gold and silver,but these were too soft for tools.On the other hand ,copper is hard enough and copper tools were much sharper than stone tools.Soo after people started using copper,they discovered that if you mix it with a little tin,you get an even stronger alloy.We call this bronze.

With their metal tools ,Bronze Age people could do many more things.In particular ,they could cut ro cut rocks to build houses ,palaces,temples and huge monuments ,like the Piramids. However ,there was a problem .Although copper was quite common ,tin was not ,so bronze was always expensive.Then,around 1500 bc people discovered a new metal-iron.Iron is a very common mineral. Almost 5% of the Earth's crust is iron and scientists believe that the red colour of the planet Mars is iron, too.With the Iton Age ,tools and weapons became a lot cheaper .

Althought iron ore is very common, people needed charcoal to make it into iron.Charcoal is made from wood and by the 18th century Europe didn't have enough trees to make charcoal.An Englishman ,Abraham Darby ,solved the problem when he discovered how to use coal instead of charcoal .Coal was very common and this led to the Industrial Revolution.People used iron and steel to build machines, steam engines,bridges, railways and many more things.

Stone,wood and metal are all natural materials.However, in the 19th century, scientists discovered that they could separate the molecules of some materials and make completely new ones.We call them synthetic materials or plastic.The first real plastic -Bakelite-appeared in 1909.Over the next thirty years other kinds of plastic ,such as PVC ,polystyrene and nylon ,appeared.Chemists are still producing new kinds of plastic today.

Dopuna: 21 Okt 2010 18:10

Ljudi ajde pomazite !! Very Happy



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Prepričavanje? Na kom jeziku? Eng-Sr, Eng-Eng, Eng-Svahili?



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  • Ben123 
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Na engleskom ! Smile (eng-eng)

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The first hand made objects produced and used by humans were made out of readily available materials, such as bone, wood and stone. However, the first metal tools, which were made out of copper appeared roughly 6,000 years ago. Details about the initial smelting process are still unknown. It is known that humans were acquainted with metals even before they started to make tools out of coper, namely with gold, and silver, but they could not be used for tool-making, since they are too ductile, unlike copper. Soon after they started processing copper, humans discovered that they can mix two or more metals, which enabled them to produce alloys. This is the beginning of the Bronze age.

Tools made out of bronze proved themselves as reliable and durable, greatly expanding the capabilities of the mankind, enabling it to start extracting and processing stone, which rendered them capable of building houses, temples, monuments and other edifices. Despite the fact that copper was readily available and easy to extract, tin was much more difficult to obtain, which made the alloy known as bronze very expensive to produce. However, about 3,500 years ago, humans discovered a new metal called iron, which could be found in abundance, since it comprises roughly 5% of the earth's crust. Hence, mass production of tools and weapons was made possible. However, initially iron-processing required large amounts of charcoal, and starting from the 18th Century, Europe was faced with a shortage of wood. The problem was solved by an Englishman, Abraham Darby, who invented the method of producing iron in blast furnaces, using coke, which is produced from coal. This was the starting point of the industrial revolution. In the 19th Century, scientists found out that they can separate molecules, and make new materials, which could replace the materials extracted from nature. These material are known as plastics, and the first plastic, called Bakelite was unveiled in 1909. After that, a whole array of other new plastic materials appeared, and the quest to produce new kinds of plastics still continues.

P.S. Nemoj ni slučajno da pomisliš ovo da kopi-pejstuješ u neki domaći zadatak, upotrebio sam dosta stručnih izraza! Mr. Green

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mozete li i meni da pomognete oko prepricavanje teksta iz engleskog? molim vas hitno je

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