tailieunhanh - IELTS Academic Reading 30

Với mong muốn giúp các bạn đạt kết quả cao trong kì thi, đã sưu tầm và chọn lọc gửi đến các bạn IELTS Academic Reading 30. Mời các bạn cùng tham khảo! | IELTS Academic Reading 30 READING PASSAGE 30 You should spend about 20 minutes on Questions 1-15 which are based on Reading Passage 30 below A spark a flint How fire leapt to life The control of fire was the first and perhaps greatest of humanity s steps towards a life-enhancing technology. To early man fire was a divine gift randomly delivered in the form of lightning forest fire or burning lava. Unable to make flame for themselves the earliest peoples probably stored fire by keeping slow burning logs alight or by carrying charcoal in pots. How and where man learnt how to produce flame at will is unknown. It was probably a secondary invention accidentally made during tool-making operations with wood or stone. Studies of primitive societies suggest that the earliest method of making fire was through friction. European peasants would insert a wooden drill in a round hole and rotate it briskly between their palms This process could be speeded up by wrapping a cord around the drill and pulling on each end. The Ancient Greeks used lenses or concave mirrors to concentrate the sun s rays and burning glasses were also used by Mexican Aztecs and the Chinese. Percussion methods of fire-lighting date back to Paleolithic times when some Stone Age tool-makers discovered that chipping flints produced sparks. The technique became more efficient after the discovery of iron about 5000 vears ago In Arctic North America the Eskimos produced a slow-burning spark by striking quartz against iron pyrites a compound that contains sulphur. The Chinese lit their fires by striking porcelain with bamboo. In Europe the combination of steel flint and tinder remained the main method of firelighting until the mid 19th century. Fire-lighting was revolutionized by the discovery of phosphorus isolated in 1669 by a German alchemist trying to transmute silver into gold. Impressed by the element s combustibility several 17th century chemists used it to manufacture fire-lighting devices but the .