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INFRARED

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  Infrared P.K.Ghatak, MD No. 72. Infrared is positioned just outside of the visual range of the humans on the Electromagnetic Spectrum. The wavelength of Infrared is between 700 nanometer to one miter. 57% heat from the sun reaches the Earth by the infrared bands (IR). Without the IR, modern warfare will grind to a halt – thermal signature of projectiles, missiles, machinery and people are precisely located and targeted to shoot them down. From the time men began lightening fire, humans understood heat carried energy from the fire to them in radiation in addition to conduction and convection. Infrared was known long before Ultraviolet was discovered. William Harshel in 1800, discovered Infrared while studying sunlight with a prism. The sun is the primary source of IR for us, in addition other celestial bodies also contribute some. People are generating IR without realizing - every time they switch on a burner, stove or light a candle one generates IR. Usefulness of infrared: Remot...
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Ultraviolet

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  Ultraviolet  P.K.Ghatak, MD No 71.  Human eyes are unable to see Ultraviolet (UV), but insects, birds and dogs are capable of seeking objects in UV. Ultraviolet light is longer than X-ray in their wavelength but shorter than the violet light on the Electromagnetic spectrum. Flowers display petals in UV light for bees and other insects to visit, offering nectar and in the process, insects pollinate flowers. A German scientist Johann Ritter was experimenting with light waves beyond the visible parts of the light. He used Silver Chloride painted papers to detect the presence of light waves and in 1801, he detected UV light. The Earth receives UV light mostly from the sun and also from Jupiter, stars, other planets of the solar system, aurora, and white dwarf. Ozone layer in the upper atmosphere blocks UV light, concentration of ozone varies based on location and presence of Ozone destroying substances made by humans.  Hummingbirds have a special retinal receptor for v...
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X-Ray

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  X-Ray or Roentgen rays. P.K.Ghatak, MD No.70. X-ray was discovered by Wilhelm Roentgen in 1895, and he was the first person to receive the Nobel Prize in Physics in 1801, for this discovery. History. Wilhelm Roentgen was born in Prussia and was educated at different schools and universities of Europe and obtained PhD in Physics from the University of Zurich in 1869. Subsequently he moved to the University of Wurzburg in Germany as a Professor in Physics. He was experimenting with vacuum tubes and external effects of passing an electric discharge through a vacuum tube, He covered the exit port of the vacuum tube with Barium Platinocyanide painted cardboard. While experimenting, he observed his own skeleton was flourishing on the cardboard. A few days later, he took picture of his wife's hand. When she saw her own skeleton, she said: “I saw my death” and X-ray was born. Madam Marie Curie revolutionized radiology by creating portable X-ray machine which was used in WW I...
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Gastropods

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  Gastropods P.K.Ghatak,MD No 69. Gastropod is a Greek word, which means mouth (gastrointestinal tract) in foot. Gastropod belongs to Mollusk phylum. The gastropod constitutes the largest family in the  Mollusum phylum, consisting of 80,000 species. They are grouped in 720 families and out of 720 families 250 are extinct. Among the living species 30,000 are marine, another 30,000 are terrestrial and the 5,000 are freshwater snail and slug species. Slugs are like sails without the external shell and most are nocturnal garden pests. Gastropods are hermaphrodites.   Snails are called Escargots in Latin and are a delicacy in France, Spain, Vietnam, Morocco and Algeria and other countries. The foot of the snail is an edible potion and is made up of proteins. The shell is not edible but the smaller the snail is, the more difficult it is to remove. The largest in size and weight of this family is Conch. Australian trumpet (Syrinx aruanus) grows to 40 lbs. and reaches 3 ft in len...
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Lightning

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   Lightning. Lightning P.K.Ghatak, MD No. 68. Lightning is a natural atmospheric phenomenon. Hot most air is lighter than cold air. When these two air masses come in close contact, a violent turbulence occurs. The moist hot air rises on the top; and as the air mass moving upwards, the water vapor in the air freezes into ice crystals and soft hails. The heavier hails fall to the bottom. The violent collision between masses of air, strips the ice crystal of its electrons and ice crystals become positively charged settle on the top of the cold air mass. The cold air mass by gaining electrons becomes negatively charged. These air masses are separated by wind pressure. The potential difference builds up and when the insulating power of the air is exceeded, an electrical discharge takes place which from the ground, we see as lightning. Lightning between air masses lights up the clouds but do not reach the ground. During rainy season, negatively charged thick air ma...
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Permafrost

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  Permafrost: P.K.Ghatak,MD No.67 When the ground remains frozen at or below 0°C (32°F) for at least two consecutive years; the Geologists designate it as Permafrost. Types of Permafrost. 1, Continuous .The entire ground remains frozen. 2, Discontinuous. Less than 100 % of the ground but more than 50% remains frozen. 3, Sporadic. Less than 50% but more than 5% remains frozen. 4, Isolated. Small patches of land here and there remain frozen. In the arctic region, the oldest permafrost has remained frozen for 700,000 years. 25% of land in the Northern Hemisphere is covered by permafrost and is located in Alaska, Canada, Siberia. Tibetan Plateau and Greenland. Much less landmass in the Southern Hemisphere is covered by permafrost and mainly found in the High Andes, Patagonia, New Zealand and Antarctica. Depth of Permafrost. It varies from less than one meter to over 1,500 meters deep. Beneficial Effects of Permafrost. Permafrost acts as a massive Carbon Dioxide sink and it holds twice...
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Our Magnetic Earth

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  Our Magnetic Earth P.K.Ghatak, MD No.66 The Earth feels solid under our feet. We live on the mantle of the Earth in geological terms. The mantle of the earth is made up of soil, sand stones and mountains. The center of the Earth, the core, is made up of iron and nickel. The outer part of the core is liquid due to very high temperature, the primordial heat retained from the day the Earth was born some 4.6 billion years ago. The center part of the core is solid because of very high pressure, about 250 gigapascals. As the earth rotates around on its axis, the liquid outer core rotates in between the solid inner core and mantle. This rotation generates electricity due to the dynamo effect. The liquid iron becomes magnetized. The compass needle points to the north direction; actually, the North is the South pole of the Earth, [the opposite poles attract each other and similar poles repulse.] In our solar system Jupiter, Saturn, Uranus and Neptune have magnetic fields. Jupiter’s magnet...
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