Category Science

How did science begin?

Science began with the wish of some prehistoric man to find out about the workings of the world about him. But the first recorded scientific discoveries are those of the ancient Babylonians who observed the positions of the sun, moon and planets. The ancient Egyptians invented simple arithmetic and geometry around 4,000 B.C. and acquired a considerable knowledge of engineering, medicine and anatomy.

      From about 600 B.C. the Greeks made great progress in philosophy and geometry, where intellectual effort only was required. But they achieved little advance in practical science, except for the discoveries of Aristotle (384-322 B.C.), who founded the study of biology. Archimedes (287-212 B.C.) discovered many simple principles of physics and Ptolemy (about A.D. 140) made advances in astronomy.

    Under Rome progress slowed down. Then the barbarians over-ran Europe and for almost 1,000 years – from 300-1100- science was kept alive first in Byzantium and then, from about 700, by the Arabs. From the 15th century, practical experiments in science began in earnest Galileo (1561626) carried out physical measurements and laboratory experiments. Francis Bacon (1561-1626) and Rene Descartes (1596-1650) pioneered the new scientific philosophy.

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Why does iron go red when heated?

Iron goes red when heated because its atoms radiate vibratory waves of an electromagnetic nature that are visible as light as a sufficiently high temperature. At 8000 C the iron is at low-red heat. But as the heat increases the iron will turn bright red, and finally white-hot and molten.

      Heat is passed through the iron by conduction-the contact of one iron particle with another with no dependence on particle movement. The heat which is given off as light when iron glows red-hot can be reconverted into heat by the substance on to which it falls. When iron is heated to a temperature below 3000 C it gives off invisible rays of infra-red radiation which are similar in nature to light. But they do not contain quite enough energy per unit (photon) to stimulate the optic nerve and do be seen by the human eye.

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How does an electric Iron work?

       An electric iron is heated by a stream of electricity passing into the heating element in its base. This element may be cast into the sole plate of the iron or clamped to the plate in a herring-bone pattern.

     Hand irons have an electric loading up to 1,000 watts and weigh from 3-6 pounds. Many of them have thermostatic control so that the correct heat is maintained. Steam irons contain reservoirs of water which release steam through holes in the sole plate directly on to the article being ironed. In this way they produce, at the same time, the moisture, heat and pressure needed to make the fibers pliable and remove the creases.

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Who sent the first radio message?

Guglielmo Marconi is usually credited with sending the first radio message. Marconi was born in Bologna, Italy; He came to England in 1896 and obtained a British patent for his wireless telegraphy system. In 1897 he established a radio transmitter on the roof of the post office at St Martin’s-Le-Grand in London, and sent a message a distance of a few hundred yards.

       He continued to improve his apparatus, and in 1898 radio was installed aboard a ship at sea, the East Goodwin lightship off the south-east coast of England. In the following year wireless messages were sent across the English Channel.

    The first radio transmission across the Atlantic was on December 12, 1901 from a station on the cliffs at poldhu, in Cornwall, and the message, three dots representing the letter S in the Morse code, was picked up at St John’s in Newfoundland.

     The existence of radio waves was first demonstrated by Heinrich Hertz, a German professor, in 1887. Marconi based his experiments on Hertz’s research.

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What is a glass made from?

Glass is made naturally from a fusion of silica (sand), soda and lime. This fusion can be achieved merely by lightning striking in a place where the right ingredients happen to be adjacent to each other. When glass is made by man, other ingredients are added, such as potash, lead oxide and boric oxide. Some of these ingredients are used to make glass clear, some to colour it, and others to give it a frosted effect.

      Glass was made by potters in Egypt for glazing stone beads as early as 12,000 B.C. As Egyptian culture progressed, craftsmen used glass for the manufacture of personal ornaments and bottles.

    A tremendous step forward in the use of glass was made by the Phoenicians in about 300 to 200 B.C. by the invention of the blow-pipe. The blowpipe is a hallow iron tube with a mouthpiece at one end and a knob shape at the other. The knob-shaped end is dipped into hot, viscous glass. A “gather” of molten glass can be blown by the worker into a hollow ball. The more he blows, the larger the ball.

    During the Roman civilization the art of glass-making reached near perfection. In the 3rd Century, the Romans cast glass on flat stones and produced the first window panes. The break-up of the Roman Empire and the ensuring Dark Ages brought an end to such cultural developments. The glazing of windows did not become wide spread over the whole of Europe until the 15th and 16th Centuries.

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Where will water boil at a low temperature?

Water will boil anywhere, but it boils at different temperature in different places. For example, it will boil at a lower temperature up a mountain than at sea level.

      The boiling point of water is the temperature at which its vapour pressure becomes equal to the outside atmospheric pressure.

     As the atmospheric pressure is always changing so the boiling point of water will vary from day to day. Water boils at 1000 C only when the atmospheric pressure outside is at the “standard” value.

    At Quito in Ecuador, this is about 2,700 metres (or 8,800 feet) above sea level, water boils at about 900 C.

    People who explore in mountainous regions find a pressure cooker very useful. The time required to cook food can be greatly reduced if the boiling point of the water is raised. The pressure cooker does this, since it is an aluminum container fitted with a loaded pin valve which allows steam to escape. The valve can be set at varying pressures, enabling the food to be cooked at a temperature of about 1200 C.

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