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combustion

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combustion: burning of a substance in the presence of oxygen to heat and light  or  burning , [1]  is a high-temperature  exothermic   redox   chemical reaction  between a  fuel  (the reductant) and an  oxidant , usually atmospheric  oxygen , that produces oxidized, often gaseous products, in a mixture termed as  smoke . Combustion in a  fire  produces a  flame , and the  heat produced can make combustion self-sustaining. Combustion is often a complicated sequence of  elementary   radical reactions .  Solid fuels , such as  wood  and  coal , first undergo  endothermic   pyrolysis  to produce gaseous fuels whose combustion then supplies the heat required to produce more of them. Combustion is often hot enough that  incandescent   light  in the form of either  glowing  or a  flame  is produced. A simple example can be seen in ...
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CLASS VIII ATMOSPHERIC PRESSURE

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CLASS VIII   ATMOSPHERIC PRESSURE
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CLASS VIII LIQUID PRESSURE

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CLASS VIII LIQUID PRESSURE CHARACTERISTICS OF LIQUID PRASSURE
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 FORCE AND PRESSURE-  CLASS VIII WHAT IS PRESSURE?                                                    
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Green leaves contain starch

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NUTRITION IN PLANTS-          CLASS VII Activity to show that green leaves contain starch
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RAFFLESIA- A PLANT THAT EATS INSECTS

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HELLO FRIENDS, Heard about rafflesia..... RAFFLESIA-INSECTIVOROUS PLANT A plant with no leaves, no roots, no stem and the biggest flower in the world sounds like the stuff of comic books or science fiction. 'It is perhaps the largest and most magnificent flower in the world' was how Sir Stamford Raffles described his discovery in 1818 of Rafflesia arnoldii, modestly named after himself and his companion, surgeon-naturalist Dr James Arnold. This jungle parasite of south-east Asia holds the all-time record-breaking bloom of 106.7 centimetres (3 ft 6 in) diameter and 11 kilograms (24 lb) weight, with petal-like lobes an inch thick. It is one of the rarest plants in the world and on the verge of extinction. As if size and rarity weren't enough, Rafflesia is also one of the world's most distasteful plants, designed to imitate rotting meat or dung. The flower is basically a pot, flanked by five lurid red-brick and spotted cream 'petals,' advertis...
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TYPES OF COAL

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                                            CONVENTIONAL SOURCE OF ENERGY-COAL                        TYPES OF COAL As geological processes apply  pressure  to dead  biotic material  over time, under suitable conditions, its  metamorphic grade  increases successively into: Peat , considered to be a precursor of coal, which has industrial importance as a fuel in some regions, for example, Ireland and Finland (In its dehydrated form, peat is a highly effective absorbent for fuel and  oil spills  on land and water, and also used as a conditioner for soil to make it more able to retain and slowly release water.) Lignite , or brown coal, the lowest rank of coal, used almost exclusively as fuel for electric power generation Jet , a compact form of lignite, sometimes polished...
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