Current Affairs 3rd Class

Living and Non-living Things    
  • Things around us can be divided into two categories man- made things Natural things
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  • The things which are made by man are called man-made things. Television, chair aeroplane, etc., examples of man-made things.
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  • The things which occur in the nature ar natural things. Trees, sun, animals rocks, etc., are examples of natural things.
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  • Natural things are again divided into two categories: living things and non-living things.
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  • The things which have life in them are called living things. Animals, people, trees are living things.
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  • The things which do not have life in them are called non-living things. Rocks, clouds water, etc., are some examples of non-livings things.
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  • Feature of livings things:
  •   (a) Living things move: Animals move from one place to another. Fish swim. Birds fly. Plants also show movement.   (b) All living things grow on their own: Seeds grow and become trees. Babies grow into men or women. Egg grow to become hen.   (c) All living things need food: To grow and live, living things need food. Without food living things cannot live and will starve to death.   (d) All living things breathe in and out: Living things cannot live without air. They take in air through nose or gills or stomata   (e) All living things grow old and die: A stone remains unchanged forever but we cannot. We grow old, become weak and die   (g) All living things reproduce: Human beings give birth to babies. Animals either lay eggs or give birth to young ones.  
  • Features of non-living reproduce:
  •   (a) Non - living things do not have life.   (b) Non - living things cannot move on their own   (c) Non - living things do not breathe.   (d) Non- living things do not grow.   (d) Non - living things do not eat food and do not grow old and die.   (f) Non - living things do not feel.   (g) Non - living things do not reproduce.  
  • Reproduction
  • The process by which living things produce their own kind is called reproduction. Only living things reproduce

    Animals and Plants    
  • Both plants and animals are living things. But they are different from each other in many ways.
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  • The following are the differences between plants and animals.
  •   (a)        Movement Animals move from one place to another. Human beings move from one place to another, birds fly and fish swim. But plants are fixed to the ground. Plants cannot move from one place to another place like animals. However, plants show movements.   (b)        Food Habits Animals have different food habits. Some animals depend completely on plants and eat them. Such animals are called herbivores or plant-eating animals, e.g., Goat, Cow. Some animals like tiger and lion eat other animals. They are called carnivores or animals that feed on other animals.   Some animals eat both plants and other animals. They are called omnivores.   All green plants produce their own food. Plants absorb water and minerals through their roots, carbon dioxide through their leaves and combine them in the presence of sunlight to make their food.   However, non-green plants like moulds and mushrooms cannot make their own food. They get their food from decaying matter in the soil.   (c)        Breathing habits Animals breathe through the nose, lungs, gills or air holes. Some animals such as insects, e.g., houseflies and cockroaches have air holes on their body to breathe. These air holes are also called spiracles. Plants have small pores on their leaves to breathe in and out. These pores are called stomata.   (d)        Reproduction Some animals like birds and snakes lay eggs while cats, dogs, lions and human beings give birth to young ones. Plants can reproduce from seeds, stems, roots, bulbs or other parts of the plant.   (e)        Sense Organs Animals have sense organs like skin, nose, eyes, ears and tongue. These organs help them to find the food and express their feelings. Plants do not have any sense organs. However they respond to light, gravity, water, etc. Some plants like touch-me-not can respond to touch.

    Animals (Their Food and Home)    
  • Animals are living things. They need food to grow and to build their bodies.
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  • Plants make their own food but animals cannot make their own food. Some animals like cows, horses, goats and sheep eat grass and other plants. They are called herbivores.
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  • Some animals like frogs, dogs, cats, lions and tigers eat the flesh of those animals which eat plants. Such animals are called carnivores.
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  • Some animals like bear and human beings eat both plants and other animals. Such animals are called omnivores.
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  • Food chains are diagrams showing the eating habits of various animals. Food chains always start with plants since they are the producers of food.
  • In the above food chain grass produces food. It can prepare food on its own. So, it is the producer. Deer cannot make its own food. It eats grass. It is a herbivore. Lion also cannot make its own food. Lion eats the deer. It is a carnivore.  
  • Some animals are useful to us. We keep such animals in our houses and farms. These animals are called domestic animals. Animals like cows, buffaloes and goats give us milk. Animals like camels, donkeys, oxen, horses and elephants carry loads and perform various works. Birds like hens and ducks give us eggs which have lots of energy.
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  • Some animals such as dogs, lions, foxes and tigers have long, sharp and pointed teeth called canines in front and sharp edged teeth at the back to carve flesh from the bones and to crack bones. They act like scissors (shears).
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  • Animals like frog, lizard, snake and crocodile do not bite or chew the food. They swallow their food as a whole.
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  • Animals like rats, rabbits and squirrels have very sharp front teeth which help them in cutting the seeds, fruits and other materials. Such teeth are called gnawing teeth and they gnaw their food.
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  • Some animals like babies of cats, dogs, cows, horses and buffaloes suck liquid food. The suck milk from their mothers.
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  • Grass-eating animals like cows, buffaloes, horses and goats have strong flat front teeth to cut the grass and leaves of the plants. They also have strong and broad back teeth to grind the food.
  •   These animals swallow the food without chewing it. After sometime they bring the food from their stomach back into the mouth and then they chew the food. This is called chewing the cud and such animals are called cud-chewing animals.  
  • The leech sucks the blood of animals like cows and buffaloes. It sticks to the animals with the help of suckers and sucks the blood.
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  • The butterfly has a long mouth part with which it sucks nectar from various flowers.
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  • Spiders make webs and traps small insects like flies and mosquitoes and then eats them.
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    Birds      
  • Birds are the most beautiful animals on earth. Most of them can fly.
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  • The body of a bird is made of a strong framework of bones. These bones are hollow and filled with air. Its body is light but strong. It is boat-shaped and so it is able to fly in the air easily.
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  • A bird has wings in place of arms. These wings have feathers which help it to fly.
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  • Birds have strong muscles which move the wings up and down. These muscles attach the wings to the breast bone and are called flight muscles.
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  • A bird's body is covered with feathers. Some of the feathers cover the body and keep it warm. These feathers are called down feathers.
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  • The feathers attached to the wings and tail-bone, help the bird to fly. These feathers are called the flight feathers.
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  • The tail of a bird acts like the rudder of a boat. It is made up of feathers and helps the bird to change its direction during flight.
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  • When a bird wants to fly, it flaps its wings and goes up gradually into the air. When the bird flaps its wings, the air under the wings pushes the bird up. When it reaches high in the air, it does not need to flap its wings any more.
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  • Bird's flight consists of two main movements. They are upstroke and down stroke. When the wings move upwards, the movement of the wings is called upstroke movement. When the wings move downwards, the movement of the wings is called down stroke movement. The tail feathers are used to steer, brake and change the direction.
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  • Birds fly to different extent. Some birds like pigeon and crow fly over long distances. In the olden days, pigeons were used to carry letters from one place to another.
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  • Birds like cock and hen fly only short distances. They usually walk.
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  • Some birds like eagle, vulture and kite fly at great heights. They have sharp eyes to locate their prey on the ground.
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  • Some birds like sparrow fly at low heights.
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  • Some birds like Kiwi, Ostrich and Penguin do not fly at all. They move on the ground with the help of their legs. Such birds are called flightless birds.
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  • Some kind of birds live in water. They have oil glands which keep their feathers waterproof.
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  • This oil does not let their feathers get wet or damaged by water. They have webbed feet to swim in the water. Ducks, swans, gulls, pelicans and cranes are some examples of water birds.

  • Beaks and Claws of Birds      
  • Birds have no teeth but they all have beaks and claws. Different kinds of birds have diffeffent kinds of beaks and claws. Beaks and claws tell us a lot about birds.
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  • Beaks help the birds to pick up their food and also to protect themselves from the enemies. Claws help in catching, holding and eating food. They protect the birds from their enemies. They help the birds in walking, in swimming, in climbing and perching.
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  • Short, hard and horny beaks can be found in sparrows, pigeons, peacocks and finches which eat nuts, grains and seeds. They break their food into small pieces with their beaks and they also use them to drive away other birds.
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  • Parrots have hooked beaks. It helps them to crack nuts and hard fruits. The curved beak helps them to eat even hard and unripe fruits. They are useful in climbing.
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  • Eagles, vultures, kites and hawks have strong, sharp and hooked beaks which help them to tear flesh into small pieces.
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  • Birds like woodpeckers which make holes in the trunks of trees to pick insects have chisel-shaped strong and heavy beaks.
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  • Swallows have short and broad beaks. Their mouths are very sticky inside. Swallows go round and round in the air with their mouth open. They catch insects and flies which stick inside their mouth.
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  • The hoopoe has a long, slender and curved beak which it uses to pull out insects from holes in the ground.
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  • Ducks have flat and broad beak. This is used for digging up the mud under water. The beak of the duck has got strainers all along the edge. Water and mud go out along these strainers and small plants or tiny water animals remain in the mouth.
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  • Kingfishers and storks have broad, long and pointed beaks which help them to catch fish from the rivers and ponds.
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  • Sunbirds have long, pointed and thin beaks. Their beaks help them to suck nectar or juice from the fruits and flowers.
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  • Perching birds like the crow, sparrow and mynahs have long, slender claws. They have four toes three in the front and one at the back. This kind of toes help the birds to hold the branches of trees firmly and they can even sleep while perching. Perching birds hop on the ground.
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  • Climbing birds like parrot and kingfisher have two toes in front and two at the back. Climbing birds can cling to the trees.
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  • Preying birds like the eagle, hank and owl have very strong and sharp claws which help them to catch and hold their prey very firmly. These birds may carry their prey to long distances.
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  • Scratching birds like hens and cocks use their claws to scratch the earth for seeds and worms. These birds have strong more...

  • Soil    
  • Soil is formed by the breaking up of rocks. By the action of sun, wind and rains rocks are broken down into small pieces. The acids produced by the roots of plants also help to break down the rocks. These pieces of rocks are carried to other places by running water and strong winds.
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  • Different places have different types of soil. The type of soil depends upon the kind of rock from which it is formed. Soils differ in the size of the grains and different constituents present in it.
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  • Most of the soils contain coarse particles of gravel, small pieces of stones, sand particles clay, moisture and humus. Humus is made up of rotten leaves and decayed bodies of plants and animals. Humus is dark brown or black in colour.
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  • There are four kings soil: gravel, sandy soil, clay and loam.
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  • Gravel is made up of very large grains which do not hold any water between them. They hold a lot of air.
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  • The sandy soil has grains smaller than those of gravel. It is grey or brown in colour. The particles are lossely packed and there is lot of air in the spaces between the particles. If we pour water on a heap of sandy soil, water sinks quickly. Sandy soil is mostly found in the deserts and on the beaches. Water drains easily through sandy soil.
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  • Clay is made up of very fine grains which stick together. Clay can hold a lot of water but very little air. Clay is used for making toys and other articles.
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  • Loam is a kind of soil which we get if we mix equal amount of sand and clay. Loam can hold enough water and air for the use of plants. Loam to which humus has been added makes a soil which is best for the growth of plants.
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    Air and Water  
  • Air and water are necessary for our living. Without them all plants and animals would die.
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  • Our earth is surrounded by a layer of air called atmosphere. Atmosphere contains oxygen. Oxygen helps to burn the food in our body and give energy.
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  • As we go higher from the earth, air decreases. On the mountains, the air is thinner.
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  • We all need water. We use water for drinking, bathing, cooking, washing our clothes, etc. Plants and animals too need water. Without water all the living things would die.
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  • The water we see is in liquid form. It can be poured into a vessel. Water takes the shape of the vessel it is in. It has no fixed shape.
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  • We cannot see or feel the water in the air because it is in the form of gas. This gas is called water vapour. When water is kept in a refrigerator it changes into ice. Ice is the solid form of water.
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  • Water can be found in three forms-solid ice, liquid form of water and gaseous form of water vapour.
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  • Seas, ocean, rivers, ponds and lakes are big resources of water. Polar ice caps and mountain peaks contain ice.
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  • When we heat a solid it becomes liquid. Ice which is a solid when heated becomes water which is a liquid. This process of heating ice to change it into water is called melting.
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  • When a liquid is heated it it becomes a gas. When liquid water is heated in a kettle we can observe steam coming out of it. Steam is nothing but water vapour. Heating water to change it into water vapour is called boiling or evaporation.
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  • When a gas is cooled it becomes liquid. When we cool the water vapour it becomes liquid water. This process of changing water vapour into water by cooling is called condensation.
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  • When liquid water is further cooled, it becomes ice. This process is called freezing. The refrigerator in our home freezes water into ice.
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  • Rain gauge is an instrument used to measure how much rain has fallen. It is a tall round metal. Can Inside this can a large collecting funnel which empties rain water into a narrow centimeters of rain has fallen.
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    Our Clothes      
  • Long long ago people wore animal skins for clothes. Today we wear clothes made of cotton, silk, wool, nylon. Clothes are of different types and made in different ways.
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  • The cotton plants have fruits or cotton bolls which burst open. The fluffy cotton inside these bolls is picked out. It has thin threads or fibres in it. They are twisted together or spun to make long threads.
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  • These cotton threads are woven together to make cloth. The weaving of the threads is done on a machine called loom. The people who weave clothes are called weavers. After weaving, the cloth may be colored or dyed.
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  • Silk clothes are made from saliva of an insect called silkworm. When the silkworm is in pupa stage it secretes saliva and builds cocoon around itself. These pupae are heated in boiling water and the worms inside are killed.
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  • Silk thread is obtained from the pupae. Then the threads are dyed and cloth is prepared.
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  • Woollen clothes are made in a General science the wool of sheep. Woolen clothes keep us warm.
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  • Naphthalene balls and dried leaves of neem keep insects away from the clothes.
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  • Nylon and terylene are synthetic fibres prepared from carbon compounds.

  • The story of Fire    
  • In the beginning, thousands of years ago man did not know how to control fire.
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  • When forest fires happened, man may have ate roasted food and liked it. Since then he started roasting roots and animal food.
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  • He kept on burning dried twigs since he did not know how to produce fire. Later, he came to know that fire can be produced by striking two stones.
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  • Fire is used to cook food and many other activities such as melting metals.
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  • Now we have kerosene stoves, matchsticks, wood, coal, petrol, LPG, etc., to produce fire. We use it as a means of energy.
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  • We should not play with fire. We should always turn off the LPG cylinder when not in use.
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    Measurements    
  • Length is measured in metres. One metre is divided into 100 centimetre and one centimetre is divided into 10 millimetres.
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  • Very long distances are measured in kilometres.
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  • Ruler, metre rod and measuring tape are some devices used to measure length.
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  • 1 kilometre = 1000 metres
  •   1 metre = 100 centimetres   1 centimetre =10 millimetres  
  • Weight is measured in grams and kilograms.
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  • Balance or weighing machine are used to easure weights.
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  • 1 kilogram = 1000 grams
  • 1 gram = 100 milligrams.  
  • Time is measured in hours, minutes and seconds. Clocks and watches are used to measure time.
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  • 1 hour = 60 minutes
  • 1 minute = 60 seconds  
  • Temperature tells us how hot or cold a body is. Thermometer is used to measure it.
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  • Temperature is measured in degrees Celsius \[[{}^\circ C]\] or degrees Fahrenheit \[[{}^\circ F]\].
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  • Clinical thermometers are used to measure body temperature. It has readings from \[35{}^\circ C\]to \[42{}^\circ C\]. The body temperature of a normal person is \[37{}^\circ C\] or \[98.6{}^\circ F\].
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  • Volume is measured in litres and millilitres.
  • 1 litre = 1000 millilitres  
  • Measuring cylinders, cans, bottles, etc., are used to measure volume.


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