chonzskypedia

   A star is a body of luminous gas, like the sun. But as stars are much farther away from the earth than the sun, they appear to be only small points of twinkling light. With the naked eye it is possible to see about 2,000 stars at any one time or place but with the most powerful telescope over 1,000 million stars are visible. Although light travels at 186,000 miles a second, the light from the stars takes many years to reach the earth.    Stars are not fixed in space, but are travelling in different directions at different speeds. Seen from the earth, these movements appear to be so  small that groups of stars, or constellations, seem to have a permanent relationship. The star patterns we see in the sky are almost the same as those seen by our ancestors hundreds, or even thousands of years ago.    The sizes of stars vary tremendously, from about a tenth of the diameter of the sun to 20 times its diameter. Most stars appear to be white when lo...

     A prime number is one that cannot be split up by division. Think of 11. Twice six is 12, three fours are 12. But the only number you can divide 11 by is one, and when you have done that you still have 11 left.      Prime numbers lie at the very roots of arithmetic, and have always fascinated those concerned with figures. Choose at random 17, 23, 29, 41, take the sequence as far as you like, and you will never find a prime number divisible by another. Over the centuries the world's finest mathematicians have tried to do so and failed although they have also been unable to prove that no such number exists. That is because there is an infinity of prime numbers, and, in theory, anything may happen in infinity. But so far the theorists have not even been able to find a rule governing the gaps between prime numbers, which is a great mathematical mystery.

What is an alchemist?     An alchemist was an early student of the science of chemistry. According to one theory the word "alchemy" is derived from "Khem", the ancient name for Egypt. That country was the source of a great deal of the pioneer work in the various sciences. Much of the early work of the alchemists is frowned on by to­day's scientists because it was bound up with experiments to find "the elixir of life" and "the philo­sopher's stone" which would turn all base metals into gold. The alchemists also studied magic and astrology. However, we have to thank the alchemists for such words as "hermetically sealed", alcohol and  alkali, and for the discoveries of sulphuric, nitric and hydrochloric acids, and of metals such as antimony, bismuth and arsenic. The "hermetic art" is another name for alchemy. Hermes Tris-megistus was the name given by the Greeks to the Egyptian god of alchemy. Thus hermeti...

     The first neon sign was made by Georges Claude in France in 1910. Neon, an inert gas, was discovered in 1898 by the British scientists Sir William Ramsay and M. W. Travers. It is colourless, odourless and tasteless and is widely distri­buted in nature. Neon is called an inert gas because it is not affected by the usual chemical reactions.  In 1850 a German physicist, Heinrich Gessler, demonstrated that a brilliant light is produced when electricity is discharged through such a gas. Neon proved to be ideal for advertising because of its unusually high electrical conductivity, its adaptibility, its high luminosity and the brilliant colours obtainable by the addition of other inert gases and mercury vapour. But neon light tubes do not give enough light for general illumination, and the colours that can be produced from it are not suitable for indoor lighting.

     Litmus paper turns red when placed in an acid solution, but blue if the solution is alkaline. This absorbent paper is the oldest and most commonly used indicator of the presence or absence of acid. Its special qualities are due to the fact that it has been soaked and impregnated with a mixture of dyes called litmus.      The litmus mixture was oroiginally produced by the action of air, ammonia and an alkali carbonate on certain lichens found in the Netherlands. It is now made from azolitmin and erythrolitmin.      A litmus solution i s sometimes used. But the message is the same. A few drops added to a liquid turns it red if acid and blue if alkaline

     Earthquakes occur mainly in the regions of the earth where mountains are being formed, and where the earth's crust is under strain.      Some mountains are formed of great thicknesses of folded sedimentary rock laid down beneath the sea. Heat currents deep within the earth are thought to suck down sections of the undersea crust and so produce great trenches thou­sands of feet deep. When the heat currents die away the material forming the bottom of the trench begins to rise because it is lighter in weight. Eventually it is thrust up as a mountain range.      This is never a smooth process but is accompanied by great friction and heat, as well as by rending and shearing and tearing. The tearing and shearing of deep under-ground rocks connected with mountain formation cause earthquakes. Even small underground movements may produce violent surface shocks. The great Tokyo earthquake of 1923 which is be­lieved to have killed 25 million ...

     An avalanche occurs when a mass of snow which has built up on a mountain side begins to slip and finally to fall. There can also be avalanches of earth, stones, rock and ice, but usually the word is used to describe a rapid fall of snow.      Snow builds up to great thickness on steep slopes, especially if the surface is not smooth. Even a very small disturbance may set it in motion. The vibration of a passing vehicle, the movement of a man or  animal, the fall of a tree branch or even a sound can cause thousands of tons of snow to crash down a mountainside.  The speed of an avalanche varies enormously, but some have been estimated to move at about 200 miles an hour. A big avalanche hurtles down the side of the moun­tain with a thunderous roar, crush­ing or sweeping away anything in its path.  The swiftly moving mass of snow pushes the air in front of it with such violence that it fans out sideways as well as driving directly a...

     A seismograph is used to measure the vibrations of the earth and to locate the source of earth vibrations. Phenomena capable of be­ing detected by a seismograph in­clude earthquakes, volcanic erup­tions, explosions such as bombs, powerful winds, violent storms at sea and even, in urban areas, traffic.  Thanks to the seismograph whole populations can be warned and prepared for a variety of natural disasters. Seismic obser­vatories around the world, have provided information increasing our knowledge of the earth's structure.      The seismograph operates on one of two basically simple mechanisms which are devices respon­sive to strain and pendulums. The earliest form of seismograph known was  been used to measure the thick­ness of the ice sheets covering the polar regions of the earth and, when used in conjunction with artificial explosions created under special test conditions, seismographs can help geologists trace oil fields.

     One of the most convincing explanations of why the continents drifted apart is that the earth expanded considerably after its creation. This theory can be illus­trated by imagining the earth as a balloon and the continents as pieces of paper stuck on the out­side. As the balloon is blown up the pieces of paper will grow farther apart.     Other theories suggest that the continents only appeared to drift apart because masses of land were drowned under volcanic waters. But it has been demonstrated that land masses are, in fact, made to drift, by the heat generated from the earth's interior and from earthquakes. Probably a combination of vari­ous theories may be necessary to provide a complete explanation.

   Artesian wells are those from which water flows freely. These wells are man-made and are crea­ted by boring into the rock to a channel that is lower than the water source. The resulting artesian well has the advantage over vertical wells of not requiring a pump. The water will pour out naturally without the aid of any mechanism until the well runs dry. For this reason arte­sian wells, although often several hundred feet deep, may be only a few inches wide. This prevents undue loss of water. The term "artesian well" is derived from Artesium, the ancient name for Artois in Northern France, where a famous free-flowing well was excavated early in the 12th Century.

   Many early maps were decorated because the map-makers or carto­graphers had little real idea of geography and presented the world in symbolical terms. One map of Roman times showed the world as a T within an 0. The 0 represented the ocean boundaries of the earth and the T the known world, with the Mediterranean as the upright and the horizontal bar as the meridian from the Nile to the River Don. Jerusalem was at the centre and elaborate decorations often included Paradise and the Last Judgment.    As the shapes of more coastlines were discovered, the unexplored land masses behind them were often filled in by map-makers with decorative portrayals of imagined animals and vegetation. The seas contained monsters and pictures of ships. Even when maps became more accurate, decorations survived be­cause cartographers saw their craft as a mixture of science and art. Some maps were specially com­missioned to be given as gifts to noble patrons or sovereigns. U...

    The land of the Midnight Sun is the poetical name for Norway. In that country from the end of April to the middle of August there is no real night darkness, but a long twilight. In the most northern part, the sun never sets com pletely for about two months in the summer. In winter, however, the most northern inhabitants are not so lucky. They have no sun for two m onths and have to eat their lunch m twilight.

     Precious stones, or gems, are minerals used for adornment, and they are found in rocks. Rocks are divided into three groups. The igneous (fire-formed) rocks may be fine-grained or coarse-grained; a very coarse-grained type, called pegmatite, is an important source of gem minerals such as diamonds. Gems are also found in the cavities of the igneous rocks granite and obsidian.      Sedimentary rocks are layered rocksand, exceptforturquoiseand opal, are the source of very few gems. However, when the original rock contained heavy minerals-and gem minerals are heavy-pebbles of them tended to be deposited as pebbles in a river bed and such deposits form the gem gravels of Upper Burma, the "byon", and those of Ceylon, the "illam". Metamorphic rocks - rocks which have been altered by pres­sure—are a fruitful source of gem minerals, for instance the rubies found in Burma. There are also precious materials of animal origin—pearls from oysters, ivory fr...

   Contour lines are used when maps are designed to show the physical nature of the land. They do this by linking all points which are the same height above sea level. The width between the contour lines indicates the steepness of gra­dients or slopes in the area. The closer the lines are together, the steeper is the slope.    On physical maps giving the height of mountains, rivers, lakes and principal towns all areas between certain heights are generally shown in the same colour. This is known as layer colouring.  Other methods for indicating heights include relief maps moulded in plastic to the physical feature raised as on a model. Spot heights may be shown, but these merely-give the heights above sea level of certain points of the map and it does not follow that the ground rises evenly from one point to another. Very old maps have mountains drawn on them. Later ones have lines called hachures radiating from a central point, with longer lines to show g...

What causes mountains? The first mountains and valleys were the crust formed as a result of the cooling of the molten mass of the earth. As the planet contracted the crust twisted and cracked, forming new mountains. Mountains are still being formed by volcanic eruption. A crack in the earth's crust allows molten rock and ash to be forced out, forming a cone-shaped mountain growing as it continues to erupt. Fault-mountains are formed when the earth's crust cracks, or faults, under pressure from inside, and one side of the break is pushed up against the other to form a cliff. The highest mountains are in the Himalayas where some are over 25,000 feet. Only in the Rocky Mountains and in the Andes are there any others over 20,000 feet.

The Northern Lights are long, waving streamers of light, often seen in the night sky in the Northern Hemisphere during both warm and cold weather. These marvellous, wavering illuminations are also called the Aurora Borealis, from the Latin words meaning a northern dawn". They are most frequently seen between 65 de­grees and 80 degrees northern latitude, but the area of visibility extends further south in North America than in Europe. The aurora of the southern hemisphere is called the Aurora Australis, from the Latin for "southern dawn". The bands of light in the aurora seem to radiate from an arc and send their rays far across the heavens. They are most often white, but are sometimes green, red or yellowish. The luminous streamers may be almost straight, or they may wind backwards and forwards like glimmering snakes in the sky. Sometimes the rays look like a fan, or form a crown round a dark centre. At other  times the  long beams of light may seem to fall downwards...

A river always takes the easiest course through channels and soft ground to the sea, flowing swiftly down mountain sides but much more slowly on the level plains. On the plain the river takes advantage of every difference in gradient. This winding course is accentuated by the process of silting and erosion. As a river flows round a curve, the water on the outer bend moves more swiftly to cover the greater distance in the same time as the water flowing past the inner bend. The more rapidly moving water will tend to wear away the bank a of the channel, while the slow or movement of the water on the inside wall will allow silting to take place. When the curve becomes more pronounced it is known as a "meander". Notable examples of meanders are to be found in the Wye in England, and the Meuse in France. Sometimes the river erodes the bank so fiercely that a new channel is formed, leaving an island of earth in the middle of the stream

Why does a compass point north and south? When the magnetic needle of a compass is allowed to move freely it will automatically place itself in line with the earth's magnetic field, one end pointing to the magnetic North Pole while the other indicates the South. Natural magnets, such as load­stone or pieces of iron which have been touched by a loadstone, are to be found the world over. It was the discovery that loadstone would always place itself so as to lie in a magnetic north-to-south position that led to the invention of the magnet. During the 15th Century it was realized that the magnetic North Pole and the Geographic North Pole were not exactly in the same place. The small angle between the two is known by seamen as "the variation". Some experts have claimed, however, that the Chinese were already aware of the existence of variation as early as the 11th Century. Again, in the 15th Cen­tury, it became apparent that the earth itself was a great magnet. ...

     Soap is made largely from fats or oil, with a variety of other in­gredients. Before the introduction of soap in the 1st Century A.D. people "washed" themselves and their clothes with fuller's earth, a fine clay-like substance that loosens oil and dirt. People first made their own soap by saving scraps of fat and boiling them in an iron pot. They added an alkaline solution, made from wood ash, called lye. This formed a yellow "soft soap", the  yellow coming from the potash in the lye. Hard soap was made by boiling for longer, and by adding salt, usually from sea-water. Soap is still made in much the same way, but on a far larger scale in modern factories. The chief things that go into its manufacture are still fat or oil (but oil from coconuts or cotton seeds), lye containing potash, or sodium, and salt. Coloured dyes, perfumes and super-fats, such as almond oil and glycerine, are added to make the expensive toilet and shaving soaps.

     What makes a mirror reflect?      It is the brightness of the mirror surface that makes it reflect light. When light falls on a surface some of the light may be reflected or thrown back, some absorbed and some allowed to pass through. In a mirror the surface is made so bright that as much light as possible is reflected and as little as possible absorbed. The earliest mirrors consisted of thin discs of metal, generally bronze, slightly convex and polished on one side. The method of making mirrors by backing glass with thin sheets of metal was known in the Middle Ages, and a guild of glass-mirror makers existed in Nurnberg, Ger­many, in 1373. The commercial manufacture of mirrors was de­veloped in 16th Century Venice. Coated mirrors were made from blown cylinders of glass which were slit, flattened on a stone, polished, and their backs silvered by an amalgam of tin and mercury. These mirrors had a high re­flecting power, but a considerable ...