Science & Mathematics Questions & Answers

Science & Mathematics Questions & Answers

Where does tobacco come from? QA For Students And Children

Kids Questionnaire - Where does tobacco come from?

Tobacco is the name given to the plant and cured leaves of Nicotiana, and it can be used in various ways – for smoking, chewing and snuffing. It was first cultivated by the Indians of North and South America. Accounts of Christopher Columbus’s first voyage in 1492 speak of the natives of Cuba using ‘smoking reeds’ – a kind of …

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What was the first life on the Earth?

What was the first life on the Earth?

Until quite recently it was thought that there were no abundant life forms on this planet until about 600 million years ago. When we remember that the Earth itself is at least 4500 million years old, it does seem to have taken a very long time before any animals or plants appeared. Then, geologically speaking, they must have developed very …

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What is the cause of the earth’s magnetic field?

What is the cause of the earth’s magnetic field?

Originally, it was thought that the centre of the earth has magnetized iron deposits, which caused it to act like a huge permanent bar magnet. However, the theory failed to explain how the magnetic field had sustained itself for long, because even if there was magnetized iron in the core earlier, the core of the earth is so hot that …

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How long has man been walking the Earth?

How long has man been walking the Earth?

Ever since the philosopher and naturalist, Charles Darwin, and his contemporaries including Wallace, suggested that man had evolved from apes, there has been a continuous, and almost frantic quest for evidence of our ancestors. Of course, where we come from has always been a fascinating question, but it is only comparatively recently that systematic searches have been made for traces …

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How is the height of different places on earth measured from the sea level?

How is the height of different places on earth measured from the sea level?

The height of different places on earth is measured with the help of the ‘altimeter’. The instrument used for measuring the height at a place is basically a barometer. At sea level, the height of the barometric liquid (mercury) is 76 cm. When we go to higher altitudes, the barometric height goes on decreasing, and right on top, where the …

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How does the Earth keep warm?

How does the Earth keep warm?

This is a question that you have answered for yourself every time that you have been sunbathing. Almost all of the Earth’s heat, and this means its energy, must come from the Sun. In addition to this the interior of the Earth has retained much of the heat which was generated as the formation of the Earth. This internal heat …

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How can we foretell Earthquake?

How can we foretell Earthquake?

China has suffered some terrible earthquakes, and it isn’t surprising that China’s scientists want to find ways of forecasting them. In 1975, they were successful. They cleared the city of Haicheng two hours before a devastating quake and saved the city’s population. Earthquake forecasting is, however, still inexact; the Chinese have failed to predict several earthquakes since 1975, but they …

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