The Stone, Bronze & Iron Ages

-

 The Stone, Bronze & Iron Ages Before 5000 BC, tools and weapons were predominantly made from stone  wood and bone, hence the term 'the Stone Age. When humans discovered that metals could be extracted from ore by using high temperatures, copper began to be used for tools, albeit to a limited degree However, sometime around 3300 BC, it was discovered that heating a mixture of copper and tin ore at the ratio 9:1 could produce an even more durable material- bronze. This began what we now refer to as the Bronze Age:


The different ages did not emerge or end everywhere simultaneously: the British Isles, for example only entered the Bronze Age in around 800 BC, and even into the 20th century several Stone Age civilisations were still being discovered.


Iron began to be used in significant quantities in the Middle East and south-east Europe around the 13th century BC, shorty after people discovered how to produce the necessary heat to smelt the Iron ore from the rock. Much stronger and more ubiquitous than copper and tin, iron gradually overtook bronze as the most sought after meal. As with the Bronze Age,  the Iron Age began at different times across the world, only reaching northern Europe around 600 BC.

Comments

Post a Comment

Popular posts from this blog

Sexually transmitted diseases(STD)

-
Image
 Unhealthy attitudes and low moral values sometimes lead to serious complications.The carrier may transmit this disease to healthy partners. 1.gonorrhoa Its is casued by gram positive bacteria (neisseria gonorrhoeae)mainly affect the mucos membrane of urinogenital tract. New born infants may acquire serious eye infections if they pass through the infected birth canal. Its is highly contagious through sexual contacts Infant infected by gonorrhoa 2.syphilis It is caused by spirochaete,treponema pallidum. It damages the reproductive organ,eye bones joints,central nervous system.Heart and skin is the major source of its spreading. Man body parts infected by syphilis 3.Genital Herpes It is caused by herpes simples type 2 virus ,mostly frequently transmitted by sexual contact causing infection of the genitalia.it prodices genital soreness and ulcer in in infected areas. In infected pregnant woman,virus can be transmitted to infant during birth ,causing damaging to eyes and CNS of the inf...
Read more

How life starts on earth

-
Image
Earth evolution  Life Approximately three and a half years ago, microscopic single-celled organisms made of complex organic molecules appeared deep in these new oceans, when the land was still a hostile place dominated by volcanoes. These organisms were the most advanced life-forms on the planet for another three billion years until suddenly (relatively speaking that is), within the period of a few million years, bacteria in the sea began processing carbon dioxide, water and sunlight to produce oxygen. This helped the single-celled microbes in the sea begin to stick to each other and create multi-cellular organisms that grew into animals. Pre life on earth was bacteria These animals began to reproduce, to evolve and eventually, when there was enough oxygen in the atmosphere to protect against the sun's radiation, to crawl onto land. Amphibians, insects, reptiles, mammals and birds all arrived on land, more or less in that order, over the next few hundred million years. At least tha...
Read more

Artificial selection of living organisms

-
Image
 The term “artificial selection” was expressed by the Persian scientist Abu Rayhan Biruni in the 11th century. Charles Darwin also used this term in his work on natural selection. He noted that many domesticated animals and plants had special properties that were developed by: •  Intentional breeding among individuals with desirable characteristics; and •  Discouraging the breeding of individuals with less desirable characteristics Artificial selection (or selective breeding) means intentional breeding between individuals for certain traits, or combination of traits. Selective breeding has revolutionized agricultural and livestock production throughout the world. Animals or plants having desirable characteristics are selected for breeding. In this way, many new generations with desirable characteristics are produced. In artificial selection, the bred animals are known as breeds, while bred plants are known as varieties or cultivars. Numerous breeds of sheep, goat, cow, he...
Read more