My Science School

The age profiles of the Dickinsonia fossils in the Maihar sandstone, determined using Zircon dating, make them comparable to those from Russia’s White Sea region, at about 555 Ma. Further proof comes from comparable Dickinsonia tenuis and Dickinsonia costata fossils in South Australia, estimated to be from 550 Ma. Studies of the rock characteristics in and around Bhimbetka show that they shared several characteristics with rocks in Australia, including “old elephant skin” texture and also a trace fossil, Prasinema gracile, the research paper notes.

Dickinsonia fossils from India were found by the scientists to be identical to the Rawnsley Quartzite in South Australia, providing evidence of their age, and the proximity of the two land masses in Gondwanaland in that era. The evidence however did not support reconstructions adjusted for the polar wander phenomenon [which involves motion of continents over geologic time and its impacts].

One distinguishing characteristic of these creatures is the absence of hard protective parts such as skeletons and carapaces (exteriors), perhaps because there were no predators. This was also the time that evidence shows some of the earliest multicellular organisms, or metazoa. The evidence comes from life forms in water when land lacked life.

 

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Dickinsonia is an extinct genus of basal animal that lived during the late Ediacaran period in what is now Australia, China, India, Russia and Ukraine. The individual Dickinsonia typically resembles a bilaterally symmetrical ribbed oval. Its affinities are presently unknown; its mode of growth is consistent with a stem-group bilaterian affinity, though some have suggested that it belongs to the fungi, or even an "extinct kingdom". The discovery of cholesterol molecules in fossils of Dickinsonia lends support to the idea that Dickinsonia was an animal.

They are nearly bilaterally symmetric, segmented, round or oval in outline, slightly expanded to one end (i.e. egg-shaped outline). The rib-like segments are radially inclined towards the wide and narrow ends, and the width and length of the segments increases towards the wide end of the fossil. The segments are separated by a thin ridge or groove along the axis of symmetry into right and left halves.

Some spectacular fossils attributed to Dickinsonia appear to preserve internal anatomy, believed to represent a tract that both digested food and distributed it throughout the organism.

 

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Researchers have discovered three fossils of the earliest known living animal — the 550-million-year-old ‘Dickinsonia’ — on the roof of the Bhimbetka Rock Shelters, about 40 km from Bhopal.

One can identify the fossils from the white leaf-like patches with a central vertebra (central midrib) and connecting veins. While one fossil is 17 inches long, the other two are much smaller.

The new discoveries, published in a journal, Gondwana Research, can be seen right at the beginning of the ‘Auditorium Cave’, the first of such caves at Bhimbetka, a UNESCO heritage site, located about 3.5 metres above the ground.

Geological Survey of India’s Bhopal in-charge Tapan Pal, who had come to visit the site, told The Hindu that they were the only such fossils available in the country, and were similar to those seen in south Australia.

 

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Everyone knows that it is cold at the North Pole – very cold. So it is reasonable to suppose that the closer you go to the pole, and the further you get from the equator, the colder it gets. Curiously, this is not entirely right. The American state of Virginia gets more snow than the lowland areas of the Arctic, even though it lies much further south. And the temperature in the northern US state of Montana has dropped several degrees below the coldest recorded at the North Pole.

It is not only how far north you go that makes a place cold. Altitude also affects temperature. The higher you are above sea level the colder it gets – and Montana is a mountainous state. The ocean plays a part too. The oceans surrounding the North Pole have several warm currents. These help to keep the temperature at the North Pole higher than it might otherwise be. However, the ocean has very little influence on the weather in the centre of a large continent – like Montana. Here the extremes of temperatures are much greater than in places closer to the ocean.

 

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Plums, cherries, apricots and peaches are among the commonest fruits with stones. The bit that interests us is the soft juicy flesh. So we tend to overlook how the fruit is put together. Look carefully at, say, a sliced peach and you’ll notice that it has three distinct layers. On the outside is the skin. Inside is the thick fleshy part that makes our mouths water. And inside that, right in the middle of the peach, is the stone. The stone is hard and we tend to chuck it in the rubbish bin without a second thought. For the peach, though, it is the most important part of the fruit because the stone consists of a hard protective shell to keep safe the seed which is inside from which another peach tree could grow.

 

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You can make bread without yeast. It is eaten in many parts of the world, particularly the Middle East. And it tastes very good. The principal difference between this and the bread we are used to eating is that bread made without yeast is flat. It does not rise.

Yeast is a mass of microscopic fungi. They produce tiny bubbles of carbon dioxide. When yeast is mixed with dough, these minute gas bubbles cause it to rise and produce the loaves of bread we buy.

 

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Because the sun rises around the world at different times, the time of day varies from one place to another. This did not cause much of a problem until people started travelling far and wide. That is when it became useful to know which day they were in. So it was decided to create an imaginary line to divide one day from the next. This is the International Date Line. It runs north-south, roughly following the 180  meridian. That is the line on the opposite side of the world to the 0  meridian, which runs through Greenwich. One or two islands get in the way and the line zigzags round these. It goes east of the Aleutian Islands on the north, then west of Fiji, Tonga and the Chatham Islands.

People going east cross the International Date Line and put their calendars back one day. People travelling west put their calendars forward a day.

 

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One of the best-known effects of the great heat that lies inside that Earth can be seen in hot, mineral springs that gush out of the surface of the Earth. These are rich in minerals such as common salt, which gives rises to ‘bitter springs’, and iron, sulphur and magnesia, giving medicinal waters.

Scientists differ in their opinions on how hot springs began. Some believe they come straight up from underneath the ground where they were trapped millions of years ago during earth movements. Other scientists think the water began as rain which seeped through the soil, became heated and then rose again.

Perhaps both opinions are correct. It is certain, however, that the waters of these springs have flowed under the soil, become enriched with mineral salts and been heated to boiling point.

 

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Lava is one of the substances that a volcano produces when it erupts. It consists of a material called magma which is a molten rock that rises from the depths of the Earth. The temperature of molten lava reaching the Earth’s surface ranges from about 700o to 1200o C. Most lava is thin and fast-moving distances.

When the volcano has stopped erupting and the lava has been exposed to the air, it begins to cool, becoming hard and rocky on the outside while remaining soft and even liquid inside. If the sides of the volcano are steep the bottom layers of the lava run off while the upper sections go hard. This process causes what is known as a lava tunnel. Soil which began its life a lava is extremely fertile. For this reason people have always lived near volcanoes despite the danger of period eruptions and the risks and the risks involved.

 

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Some 90 per cent of the chewing gum produced in the United States comes from chicle, the solidified milky juice of the sapodilla tree. This is a tropical evergreen which grows to more than 15 metres in height and has many branched with glossy, light green leaves that are oval in shape. The trees grow wild in the forests of southern Mexico and northern Central America.

The wood of the sapodilla is very hard and stands up well to bad weather, the Mays , the ancient people who lived in Central America, used sapodilla wood for building, and many examples of this wood, still in good condition, have been found in Maya ruins.

The fruit of the sapodilla tree contains a jelly-like fluid. When this fluid hardens it turns into a pink gum that can be chewed. The material most used in making chewing gum is the latex, or milky most used in making chewing gum is the latex is obtained by making deep V-shaped cuts in the bark of the tree; the juice runs down these cuts and is gathered in cups. The latex is taken from the tree during the rainy season when the sapodilla tree has the most juice.

 

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In 1945 the Allies launched stronger attacks against Japan. Because of the great combat range of the B-29 bomber, the aeroplane known as the ‘flying fortress’, the Americans were able to carry out air raids every day on Japanese territory. The cities of Japan were very densely populated and many of the houses were made of wood. When the bombs fell these buildings burned like tinder. In the last few months of the Second World War, from March 1945, American aeroplanes dropped many tons of fire bombs on the principal Japanese cities. About 250000 people were killed in these air raids and houses over an area of more than 450 square kilometres were burned to the ground. On the night of 9 March 1945, American B-9 bombers from air bases in the Marianne Islands in the Pacific Ocean flew at almost 1,500 metres above Tokyo and devastated the Japanese capital with fire bombs. In that one night alone almost 38 square kilometres of the city was burned to the ground.

On 6 August 1945, a B-29 bomber dropped one solitary bomb on the city of Hiroshima. The bomb was light compared with some the huge bombs previously dropped on enemy cities, but this was an atomic bomb previously dropped on enemy cities, but this was an atomic bomb and its terrible explosive T.N.T. going off. The first atomic bomb destroyed 60 percent of Hiroshima and killed about 80,000 men, women and children. Three days later the city of Nagasaki was attacked by air with a second atomic bomb. The effects of these bombs were terrible. The two explosions brought an end to the world war which had raged for almost six years.

 

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Sometimes when the thirsty traveler makes his way through the burning sands of the desert a lake suddenly appears before him just over on the horizon. The traveler then makes haste to reach this totally unexpected and welcome place welcome place of refreshment. Of course, the lake is not really there and what traveler sees is a mirage.

For a long time people thought mirages were hallucinations, an unreal vision like a dream that some people experience when they are ill. Then it was perfectly well, who were not hungry or thirsty. It was then learned that mirages are an optical illusion, a trick played by the air.

The temperature of the air we breathe differs according to the altitude. In the desert, air is warmer near the ground, which can extremely hot on summer days, and grows cooler as it rises upwards. Warm air is less dense than cool air and acts as a mirror or pool of water to reflect light. The reflections are often seen upside down as trees are in a still pool of water to reflect light. The reflections are often seen upside down as trees are in still pool of water. The warm, dense air also reflects the sky and the shimmering effect on the ground looks like a lake or pool.

 

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Man has always longed to fly. In the late fifteenth century, Leonardo da Vinci was working on the problem of flying and a century later, a Jesuit priest from Brescia in northern Italy, suggested using the ascending force of the lightest gases present in the air. In 1782, the Neopolitan, Tibero Cavallo, filled a balloon with hydrogen and carried out some laboratory tests.

In France, a balloon full of hot air was publicly launched on 4 June 1783 at Annonay by the Montgolfier brothers, Etienne and Joseph. They repeated the experiment with a larger balloon at Versailles on 19 September 1783 when a hen, a sheep and a duck were the first living creatures to go up in a ‘Montgolfier balloon’. On 21 November the Marquis of Arlandes and Pilatre de Rozier, flew across from Paris, on board a hot air balloon.

The following month, December 1783, hydrogen was substituted for hot air. The physical J.H.C Charles with M.N Robert made the first manned flight using hydrogen.

 

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An important world record in the field of nuclear science is held by Britain, where the world’s first atomic power station was built in 1956 at Calder Hall.

Since then, the generation of electric power by atomic or nuclear reactors has become increasingly important in Europe, where over 10 percent of total generating capacity is now nuclear. This is a higher proportion than in any other continent.

The leading European nuclear country in terms of nuclear power stations is France, which generates about a third of its electricity from nuclear fuels. Then come Germany, Britain, Sweden, Finland, Spain, Switzerland, Belgium, Bulgaria, Italy, Czechoslovakia, Yugoslavia and The Netherlands.

British nuclear power stations use a variety of different kinds of reactors, including an experimental fast breeder reactor at Dounreay. This is a kind of reactor that produces more fuel than it consumes and it could in theory generate immense amounts of power in the future.

However the technological problems involved have proved extremely difficult to solve and it is now doubtful whether the fast breeder will ever fulfil its early promise. Although nuclear power stations have to date worked well and safely throughout Europe, there is a mounting problem of radioactive waste disposal.                                                                                                                                                                                                          

 

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Much of the hail that falls on Europe occurs in summer though scientists believe it is caused by cold temperatures. Some meteorologists believe hail is formed when a current of hot air rises to about 1,000 to 2,000 metres and collides with a cold air current that is descending. The sudden lowering of the temperature in the warm air current freezes the moist air it contains into the little pellets of ice that form hail. This process may be repeated several times, the hailstone gathering more and more coatings of ice, until it becomes heavy and falls.

Other meteorologists think that hail is produced by electrical processes.

Whatever the cause hail is a constant threat to farmers who for centuries have sought ways of defending their fields from it. Hailstorms do not usually affect large areas, but they can be so concentrated and intense that they destroy an entire year’s crop wherever they strike. Vineyards are frequently affected in this way.

 

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