Current Affairs 3rd Class

The Earth and the Moon    

We all live on the Earth. Earth is a big, round and slightly flattened at the poles. Our Earth consists of three things: land, water and air.

 

During eclipse, Earth casts round shadow on the Moon. If we observe ship sailing away from us, the hull disappears first, then the top of the mast. These two things tell us that the Earth is round in shape.

 

There are nine planets revolving around the sun in the order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. Planets do not glow on their own but stars like sun glow. The Earth is about 150 million kilometres away from the Sun.

 

The Earth has two types of movements: rotation and revolution.

 

The Earth spins around itself on an axis. This motion around its own axis is called the rotation of the earth. The Earth completes one rotation in 24 hours. It spins from west to east.

 

The rotation of Earth produces day and night. The part of the Earth which faces the Sun and gets light has a day while the other half of the Earth which is away from the Sun and does not get the light has a night.

 

The Earth rotates around the Sun in 365. days. This motion is called revolution. The revolution of earth gives rise to different seasons.

 

Sun is a big ball of burning gases which is very hot. Sun looks small because it is 150 million kilometres away from us but actually it is very very bigger than the Earth. All planets revolve around sun.

 

Moon is a natural satellite of the Earth. It is smaller than the Earth and takes about 28 days to complete one revolution around the Earth. It is about 384,400 km away from us. It has no light of its own but reflects the light of the Sun.

 

We see different shapes of the Moon. When we See the complete Moon like a round ball we call it full moon. The full moon day is called purnima. When we do not see the lighted face of the Moon, it is the new moon. The new moon day is called amavasya. When it is a crescent moon we see only a part of its lighted face.

 

It is a full moon when the Earth lies between the Sun and the Moon. It is a new Moon when the Moon lies between the Sun and the Earth.

 

Stars are big heavenly objects which can emit heat and light on their own. Some stars occur in groups and interesting shapes. Such groups are called constellations.

   

Our Body  

Our body is like a living machine which can see, hear, smell, taste, move, grow, breathe and reproduce.

 

Our body is made up of many different parts called organs. Each organ has its own role to play.

 

The organs which help us to feel or sense the things around us are called sense organs. We have five sense organs: eyes, ears, nose, tongue and skin. These organs help us to see, hear, smell, taste and feel.

 

Sense organs take messages from the outside world and send them to the brain through nerves. After receiving the messages from the sense organs, the brain passes orders to the different organs of the body. Then the body works according to the orders.

 

The eyes help us to see the objects. We can see near and distant objects and know the shape, size and colour of the objects. Eyes give us the sense of sight.

 

The ears help us hear all types of sounds. They give us the sense of hearing.

 

The nose helps us to smell different kinds of things. We can distinguish between sweet smell or a foul smell. Nose helps us in the sense of smell.

 

The tongue helps us to taste things and helps in the sense of taste. We can taste sweet, sour, salty and bitter flavours.

 

The skin gives us the sense of feeling. It gives us the feeling of cold, hot, pain, pressure, touch, etc. It also helps us to feel if a thing is smooth or rough.

 

Organs of our body do not work alone. A number of organs in our body are connected together to do a particular kind of work. Such kind of arrangement is called an organ system.

 

Skeleton system is made up of bones and forms framework of the body. It gives form, shape and support to our body we can stand, sit, walk and move because of our bones. There are 206 bones in our body.

 

Nervous system consists of brain and nerve. It receives messages from the sense organs and other parts of the body and sends orders for the action. It controls all our actions of seeing, hearing, speaking, learning, thinking, etc.

 

Muscular system is made up of muscles. Most of the muscles are fixed to the bones. Bones and muscles work together. This system helps us to move about and do different kinds of work.

Respiratory system helps us to take in air from outside. We breathe in air through our nose. The hair present in the nose stop dust and germs from the air. Thus, the fresh air from the nose enters the lungs. In the lungs the blood takes oxygen from the air. This oxygen is used to 'burn' the food to get energy. The air we breathe out has carbon dioxide and is impure.

 

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Safety and First Aid      

To prevent accidents and injuries, we should follow certain rules. These are called safety rules.

 

Safety rules at home :

We should use sharp-edged things like blades, scissors and knives very carefully. We should not leave bags and shoes on the floor. We should not play with fire and electrical appliances.  

We should not touch electric wires. We should not take medicines without consulting elders and doctors. We should fly kites in the parks or open grounds but not on the terrace.

 

Safety rules in the classroom :

We should not jump on the desks or benches and should not throw chalk pieces or dusters. We should use pencil sharpeners and not blades. We should not play in the classroom.  

Safety rules on the playground :

We should learn and follow the rules of game. We should not hit others with bat or quarrel with playmates. We should not play near thorny hedges or barbed wires. We should share toys or sports material with others.  

Safety rules on the road

We should not rush down the stairs. In the school, we should go up and down the stairs in a line. We should not pull or push other children.  

Since accidents do take place, we should give help to the injured person in the time a doctor or an elder comes. This is called first aird.

 

When an accident occurs we should not get frightened or panic and we should not crowd around the person who is hurt. If a person falls down, run and help him. If he is hurf, we bandage around the wound and call the elders or doctors

A Good House and Surroundings      

A good house should be clean and airy with windows and ventilators. Sunlight and fresh air keep the rooms dry and free from germs. A good house should have separate place for eating, sleeping, studying, cooking, washing and storage.

 

A good house should have an open space for sitting out and for the children to play. It should have bolts on the doors and windows and locks on the cupboards.

 

A good house should have proper drains to take away dirty water from the kitchen and bathrooms. It should have proper chimneys to let the smoke out.

 

To keep our houses clean, we should keep our surroundings also clean. If our surroundings have garbage, they attract flies and germs which cause diseases.

 

We should not throw our garbage around and make the surroundings dirty. The household garbage should be kept in closed dustbins. These dustbins should be taken to municipal bins or garbage dumps. Municipal trucks will carry this garbage away from the city.

 

We should not let waste water to flow into open space and stagnate it near the houses. Mosquitoes breed in stagnated water and cause malaria. We should dispose waste water through drains. We should spray kerosene on stagnated water to kill mosquitoes.

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.

 

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.

 

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.

 

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.

 

Silk thread is obtained from the pupae. Then the threads are dyed and cloth is prepared.

 

Woollen clothes are made in a General science the wool of sheep. Woolen clothes keep us warm.

 

Naphthalene balls and dried leaves of neem keep insects away from the clothes.

 

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.

 

When forest fires happened, man may have ate roasted food and liked it. Since then he started roasting roots and animal food.

 

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.

 

Fire is used to cook food and many other activities such as melting metals.

 

Now we have kerosene stoves, matchsticks, wood, coal, petrol, LPG, etc., to produce fire. We use it as a means of energy.

 

We should not play with fire. We should always turn off the LPG cylinder when not in use.

 

Measurements    

Length is measured in metres. One metre is divided into 100 centimetre and one centimetre is divided into 10 millimetres.

 

Very long distances are measured in kilometres.

 

Ruler, metre rod and measuring tape are some devices used to measure length.

 

1 kilometre = 1000 metres

  1 metre = 100 centimetres   1 centimetre =10 millimetres  

Weight is measured in grams and kilograms.

 

Balance or weighing machine are used to easure weights.

 

1 kilogram = 1000 grams

1 gram = 100 milligrams.  

Time is measured in hours, minutes and seconds. Clocks and watches are used to measure time.

 

1 hour = 60 minutes

1 minute = 60 seconds  

Temperature tells us how hot or cold a body is. Thermometer is used to measure it.

 

Temperature is measured in degrees Celsius \[[{}^\circ C]\] or degrees Fahrenheit \[[{}^\circ F]\].

 

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 \[98.6{}^\circ F\].

 

Volume is measured in litres and millilitres.

1 litre = 1000 millilitres  

Measuring cylinders, cans, bottles, etc., are used to measure volume.

Means of Communications  

The developments in science and technology are shrinking the world in communication and transportation.

 

It took seven years of dedicated hard work to the Wright brothers, Wilbur Wright and Orville Wright, to invent the aeroplane.

 

Nowadays, with the advanced aeroplanes we can travel thousands of kilometres in few hours.

 

People staying in different places can exchange information by writing letters.

 

Urgent messages can be passed through telegrams.

 

Parcels and documents can be sent from one place to another place through speed post and courier.

 

We can talk instantly with others through telephone. STD facility connects different telephones within our country and ISD connects telephones in different countries.

 

Mobile telephone or cellular phones can be carried along with the person.

 

Wireless communication system is useful for the people working in police and army.

 

With pagers, messages can be sent instantly.

 

Through fax we can send written and printed material.

 

Radio is an effective means to broadcast audio signals.

 

With television we can broadcast both pictures and sound.

 

With computer and internet we can send and receive large amounts of information from the entire world.

   

With the help of E-mail, we can send and receive messages from anywhere in the world through the computers connected to internet.

                                                                      Animal Kingdom     Land Animals Dog, cat, elephant, zebra, cow, etc. are the examples of land animals Animals that live on land are called land animals.   Characteristics of Land Animals Land animals have certain characteristics that distinguish them from other animals. They are as follows:   Land animals move or crawl Most of the land animals move or crawl in search of food and shelter. For example, lion, tiger, snake, etc. Kangaroo is an animal that hops.   Land animals do not make their own food Land animals depend on plants or other animals for their food. For example, cow eats grass, lion eats deer and deer again eats grass etc. This is like a chain that the plants and animals form.   Food Chain   Land animals take oxygen directly from air Land animals take oxygen directly from air and utilize it to get energy.   Land animals produce sound Most of the land animals produce sound. For example, cat mews, dog barks, etc.   Land animals reproduce Land animals reproduce by laying eggs or by giving birth to young ones.   Land animals have tail Most of the land animals have tail that help them in their movement. Tail also help them to maintain the body balance. For example, lion, elephant, dog, cat, etc.   Classification of Land Animals Land animals are divided into: (i) Domestic animals (ii) Wild animals   Domestic Animals Animals that live with us are called domestic animals. For example, dog, cat, etc.   Wild Animals Animals that live in the forest are called wild animals, .or example, lion, tiger etc. Land animals are classified also: (i) Milk giving animals (ii) Draught animals   Milk Giving Animals Animals that give us milk are called milk giving animals. For example, cow, buffalo, etc.   Draught Animals Animal that work and carry load for us are called draught animals. For example, ox, horse, etc. In the third category, the land animals are classified as. (i) Herbivorous animals (ii) Carnivorous animals (iii) Omnivorous animals   Herbivorous Animals Animals that eat plants are called herbivorous animals.   Carnivorous Animals Animals that eat flesh are called carnivorous animals.   Omnivorous Animals Animals that eat both plants and flesh are called omnivorous animals.   Mammals Animals which give birth to babies are called mammals. For example, human being, dog, whale, dolphin, etc.   Aquatic Animals Aquatic animals live in water. For example, fish, dolphin, whale, etc. Aquatic animals also live in lakes, oceans and rivers. Some animals like tortoise, frog, etc. live both on land and in water and are called amphibians.   Classification of Aquatic Animals Aquatic animals can be classified on the basis of: (i) Their habitat (the kind of water they live in) (ii) Food (the type of food they take in)   Classification on the basis of habitat:   Fresh water animals They are the animals that live in rivers, more...

                                                              Plants Kingdom   Plants are one of the most important living things that have made the life possible on Earth. They are the only source of life giving oxygen. Plants breathe in harmful carbon dioxide gas and breathe out oxygen.                                                                                                                                                        Tree Characteristics of Plants Plants Make their Own Food Green plants are autotrophs. They make their own food in the presence of carbon dioxide, water and sunlight. Green plants have a pigment called chlorophyll that helps them to make food.   Plants have Roots and Shoots Root grows under the ground and shoot grows above the ground.   Plant    Many Plants bear Fruits Many plants bear fruits that are very nutritious and delicious.   Mango Tree   Plants Reproduce Plants reproduce to continue their existence. They reproduce with the help of seeds, stems and roots.   Plants Grow throughout their Life Cycle Most of the plants grow throughout their life cycle. They attain maximum height.   Few Plants have Thorns For example, rose, cactus, etc.   Leaves of a Plant Plants make food in the leaves. Therefore, leaf is called the kitchen of the plant. Plants get energy from this food. There is a small opening in the leaf. It is called stomata. Plants breathe through this opening. Plant's leaves can be of different shapes. For example, leaves can be round, long or triangular.                       Long leave                        Round leave                   Triangular leave (Mango)                 (Lotus)                                  (Peepal)   Leaves of many plants are used to cure diseases. For example, neem's leaves cure skin problem.   Classification of Plants Plants are classified into three types:   Trees Plants having tall and hard trunks are called trees. Trees have thick and woody branches. For example, mango tree. Banyan tree, etc.   Herbs Plants having weak and soft stem are called herbs. For example, tulsi, mint, etc.   Shrubs Scrubs are taller than herbs and have multiple woody stems. For example, rose plant sunflower, etc.