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Old Wednesday, November 16, 2011
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Short Note (Solar System)


Lunar Eclipse:
The partial or complete obscuration of light of moon for an observer on the earth is called lunar eclipse.
Lunar eclipse takes place when the earth comes in position between the sun and the moon. In this way, the shadow of the earth is cast on the moon and the moon does not get sunlight in this position.
Lunar eclipse occurs only when there is full moon. But this does not happen on every full moon because of inclination of the axis of earth to its orbit.

Solar Eclipse:
Solar eclipse occurs when the moon comes in between the Sun and the earth and its shadow is cast across the face of the earth.
The solar eclipse occurs when the moon moves to a position between the Sun and the Earth. During this process it throws shadow on the earth. This shadow is categorized in umbral and penumbra. The people who are in the umbral region are unable to see the sun at all. This condition is known as the total eclipse of the sun. While the people in penumbra region can see the sun partly this is known as the partial eclipse of the sun.
This happens with the new moon when the moon is in conjunction with the sun. this does not happen at every new moon because of the inclination of the orbit of the moon to the orbit of earth around the sun.

Asteroids:
Asteroids are also known as planetoids. These are small, irregularly shaped rocky objects which orbit the Sun between the orbits of Mars and Jupiter. Asteroids are also known as the minor planets.
Basically the word Asteroid means “Starlike”. Ceres asteroid was the first to be discovered.

Meteorites:
Meteorites are small chunks of iron and rock thought to be resulted from collisions between asteroids. They also may be formed when comets disintegrate into fragments. Meteorites enter the earth’s atmosphere and become a meteor. A meteor is a “falling star” that is usually seen in the sky at night. A meteor will burn up from frictional heating as it enters the atmosphere. Most of the meteors burn up before they reach the earth. If they do not reach the ground they become meteorites. Meteorites can be seen at a distance of 70 miles from the earth. Meteorites are heavy objects which weigh about 60 tons.

Comets:
Comets are those bodies which revolve round the sun. they are mainly composed of ice and dust. Most comets have three parts which are as under.
i) A solid centre.
ii) A head or round coma, that surrounds the centre and consists of dust particles mixed with frozen water, frozen methane and frozen water, frozen methane and frozen ammonia.
iii) A long tail of dust and gases that escape from the head. Most comets stay near the solar system.
Other characteristics of comets are as under:
• Comet is usually about 10 km or 6 miles across.
• Comets are usually made up of ice and dust.
• Millions of comets are present in the solar system.
• Halley’s comet is the famous example.
• Comets usually move around the sun in the elliptical orbits.

Light Year:
The distance travelled by light at speed of 186,000 miles per seconds in one year is known as a light year. One light year is approximately 9461,000 million kilometres or 5875000 miles. Light year is also used to measure the distance between the galaxies.

Astronomical Unit:
The distance between the Sun and the Earth is called as Astronomical Unit. This unit is also used in the measurement of distances between the heavenly bodies within the solar system. The earth is one A.U away from the Sun and the Pluto is 39 A.U away from the Earth.

Black hole:
Black Hole is a hypothetical region in space which has a big gravitational pull for which no matter or radiation can escape from it. Even it is believed that light cannot escape from it. Black Hole usually likes at the centre of galaxy.

Super Nova:
A Super Nova is an exploding star. At the end of its phase as a Red Giant, a heavy star explodes as a Supernova shining briefly as brightly as a thousand million stars. Recent Supernova was observed on the night of Feb 23, 1987. This occurred in Large Magellanic Cloud.

Nebula:
Nebula is derived from a Greek word which means “Cloud”. In the sky there are clouds like objects, which are classified as Nebulae. There are both luminous diffuse nebulae and dark obscuring nebulae over the Milky Way. They are made up of dust and gases.

Aurora:
Aurora or Kutub-i-Raushani is a luminous meteoric phenomenon of electrical character seen in Polar Regions with a tremulous motion and giving forth streams of eight Aurora. It is generally believed that the aurora is actually caused by radiation from the Sun-spots.

Solar Wind:
Solar wind is the stream of electrically charged particles especially protons and electrons, which are emitted by the Sun, predominantly during solar flares and sunspots activity. Some of these particles become trapped in the Earth’s magnetic field forming the outer Van Allen radiation belt, but some penetrate into the upper atmosphere where they congregate in narrow zones in the region of the Earth’s magnetic poles producing aurora displays.

Cosmic Rays:
Cosmic Rays are charged particles moving as fast as the speed of light. Most of the particles are protons, while some are alpha particles and electrons. They travel throughout our galaxy, including the solar system and some strike the earth’s atmosphere. They can be detected by instruments on the Earth. Nobody knows how cosmic rays are formed. Some of them are formed by exploding stars or supernova and some come from outside our Galaxy.
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Some Important Definitions:


Cosmology:
Cosmology is the science of the cosmos or universe.
OR
Cosmology is the branch of physical science which deals with the Universe.

Universe:
The universe is the sum total of all that exists, or has existed, both in space and time.

Galaxy:
A galaxy is a system of many thousands of millions of stars together with inter-stellar gas and dust.
OR
Galaxy is a fundamental unit of the universe. It is composed of hundreds of thousands of stars together with intra-stellar gas and dust.

Star:
Those heavenly bodies which are luminous and produce their own energy by nuclear reactions are called stars.
• Proximal Centauri second nearest after Sun to the Earth.
• Antares is one of the largest stars known.

Solar system:
A tiny system of our galaxy which consists of the /sun, a planet and their satellites, thousands of miniature planets called asteroids, meteoroids, comets, interplanetary dust and plasma.

Satellite:
Those heavenly bodies which revolve round the planets are called satellites.

Eclipse:
In astronomy, the term eclipse simply means the obscuring of one heavenly body by another, particularly that of the sun or a planetary satellite.

Lunar Eclipse:
A condition when the earth comes in between the sun and the moon and throws its shadow on the moon is called lunar eclipse.

Solar Eclipse:
A condition when the moon comes in between the sun and the moon and throws its shadow on the moon is called Solar Eclipse.

Astrology:
Astrology is the interpretation of the influence of planets and stars on human lives.

Asteroids:
Small, irregular shaped rocky objects which orbit the sun between the orbits of Mars and Jupiter are called Asteroids.

Meteorites:
Tiny chunk of material floating in space which can also enter the earth’s atmosphere and become meteor are known as meteorites.

Comets:
The bodies mainly composed of ice and dust which revolve round the sun are called comets.
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Balanced Diet:


• “The food which contains all essential food nutrients which are necessary and essential for healthy growth of the body and proper functioning of the whole parts of body.”

• Food is a complex mixture of chemical substances.

• It performs following useful functions when eaten and absorbed by the body.
i) Produces energy
ii) Promote growth
iii) Repair the tissues
iv) Regulate various processes


• Nutrients are the chemical components of food capable of performing above functions.

• Example: milk is a balanced diet although it does not contain iron.

• Following are the major components of Balanced Diet and their source and functions:

i) Carbohydrates
Source: Honey, Sugarcane, Wheat, Maize, Potatoes.
Functions: Provide energy

ii) Fats:
Source: Butter, Cheese, Soya bean, Mustard etc.
Functions: Provide Energy

iii) Proteins:
Source: Meat, Eggs, Fish, Milk, Pulses etc.
Functions: Essential for growth

iv) Vitamins:
Source: Fruits and Vegetables.
Functions: Important for proper physiologic and metabolic functions of the body.
Types:
a) Water Soluble Vitamins: B1, B2, B6, B12, C
b) Fat Soluble vitamins: A, D, E, K

v) Minerals: Minerals are those inorganic substances which play a key role in the maintenance and building of the body tissues. The most important minerals of balanced diet are as under:
Phosphorus: is necessary for bones and teeth.
Iron: is an essential component of blood.
Iodine: is necessary for thyroxin which is secreted from thyroid gland.
Calcium: is necessary for bone development.

vi) Water:
Source: Fruits, Vegetables
Functions: It is constituent of blood, lymph, hormones and other secretions of the body.
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Functions Of Vitamins:


1. Vitamin A
i) Role: Vitamin A plays an important role in growth and body repair, keeps the skin smooth and essential for vision.
ii) Deficiency: it deficiency causes “Night Blindness”.
iii) Source: Fortified milk, butter, eggs, cream, leafy vegetables, carrot.

2. Vitamin B1
i) Role: it is an energy building vitamin, help in the digestion of carbohydrates, keep the heart and muscle stable and necessary for nerves.
ii) Deficiency: its deficiency causes Beri Beri, muscular weakness, cramps and heart swelling.
iii) Source: Pork, cereals, legumes, nuts and seeds.

3. Vitamin B2 (Riboflavin)
i) Role: It is important in forming RBCs, protection of mouth and mucous membrane and skin.
ii) Deficiency: its deficiency causes “Pellagra”
iii) Source: Milk, leafy green vegetables, cereals etc.

4. Vitamin B3 (Niacin)
i) Role: Helps in releasing energy from carbohydrates, fats and proteins, very essential for the DNA synthesis, used to lower elevated LDL cholesterol and triglyceride levels in the blood, boosts the level of HDL, the 'good' cholesterol, in the body, essential for the proper digestion of the food etc.
ii) Deficiency: its deficiency causes Loss of appetite, Indigestion, Skin lesions, Mental imbalance etc.
iii) Source: Meat, poultry, fish, cereals, vegetables, peanuts, butter etc.

5. Vitamin B6 (Pyridoxine)
i) Role: it is essential for the production of antibodies, for the CNS and help in protein metabolism in the body.
ii) Deficiency: Skin problems, Nervous system disorders, Muscle spasms, Sleeplessness.
iii) Source: Meat, fish, poultry, vegetables, fruits etc.

6. Vitamin B12 (Cynocobalamin)
i) Role: it is important for carbohydrate and fat metabolism, growth of child and formation of blood.
ii) Deficiency: its deficiency causes “anaemia”
iii) Source: Meat, poultry, fish, seafood, eggs, milk.

7. Vitamin C (Ascorbic Acid)
i) Role: It is essential for protection of bones and for healthy teeth and gums.
ii) Deficiency: its deficiency causes “Scurvy”
iii) Source: Citrus fruit, guava, pineapple, tomatoes, spinach, turnips, strawberry.

8. Vitamin D:
i) Role: It is very important for the growth of children.
ii) Deficiency: Its deficiency causes “Rickets” in children and Osteoporosis in adults.
iii) Source: Egg yolk, liver, fish, milk.

9. Vitamin E:
i) Role: it plays an important role in wound healing, prevention of sterility, breaking blood clots and prevents damage of cells due to aging.
ii) Source: Leafy green vegetables, soya bean, cotton seed, liver, egg yolk, nuts etc.
iii) Deficiency: its deficiency slows down the formation of RBCs.

10. Vitamin K:
i) Role: essential for blood clotting.
ii) Deficiency: its deficiency causes “Blood clotting Disorder”
iii) Source: Leafy green vegetables, milk, fish, liver, alfalfa.
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Minerals: Their Functions, Source and Sings Of Deficiency:


1. Calcium:
i) Role:
a) It is essential constituent of bones and teeth.
b) It is vital for metabolic process such as nerve function, muscle contraction, and blood clotting.
ii) Source: Dairy Products
iii) Deficiency: Osteomalacia (softening of bones), Osteoporosis, Rickets, Tetany

2. Iron:
i) Role: It is the key constituent of haemoglobin which helps in transfer of oxygen.
ii) Source: Eggs, Green Vegetables, Fortified foods, Cereals, White flour, Liver, Meat, Nuts, Peas.
iii) Deficiency: Anaemia, Increased susceptibility to infection.

3. Magnesium:
i) Role: it is essential for healthy bones; muscles and nervous tissues. It is needed for functioning of approx. 90 enzymes.
ii) Source: Eggs, leafy vegetables, fish, milk and dairy products.
iii) Deficiency: Anxiety, fatigue, insomnia, muscle problem, nausea, premenstrual problem.

4. Phosphorus:
i) Role: it is important for healthy bone tissues.
ii) Source: Dairy products, fruits, meat, pulses, leafy vegetables.
iii) Deficiency: Anaemia, demineralization of bones, nerve disorder, respirator problem, weakness, weight loss.

5. Potassium:
i) Role: it is essential for intracellular fluid, maintenance of electrical potential of the nervous system and functioning of muscle and nerve tissues.
ii) Source: Cereals, coffee, fresh fruits, meat, vegetables, whole-grains, flour.
iii) Deficiency: General muscle paralysis and metabolic disorder.

6. Sodium:
i) Role: it is necessary for the control of the volume of extra cellular fluid in the body maintenance of pH of the body, and electrical potentials of the nervous system.
ii) Source: Bakery products, Table salts
iii) Deficiency: Low blood pressure, general muscle weakness, respiratory problems.
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Computer:


“The word Computer is derived from compute which means to calculate. In simple and technical term it is an automatic electronic calculating machine that processes or manipulates a given data according to a program or set of instructions and gives a desired output.”


Parts Of A Computer:

The computer is composed of two parts:
1) Hardware
2) Software

1) Hardware:
All physical components of computer, which can be touched, measured, have weight and occupy space, are collectively called computer hardware viz;
i) Keyboard
ii) Mouse
iii) Joy stick
iv) Scanners
v) Monitor
vi) Printer
vii) Central Processing unit etc.

2) Software:
Software can be defined as a set of instructions or codes written in a defined manner. In other words softwares are prewritten programs, which control the operations of computer.

OR
All programs and data stored on floppy disk, Hard disk, CD-ROM are collectively called softwares. Examples are;
i) DOS
ii) Window
iii) UNIX
iv) XENIX
v) Linus
vi) Java
vii) MS Office

Devices OR Components Of A Computer:
The computer is a combination of many parts, each of which performs specific task independently. The major devices of a computer are as under.

1) Input Devices
The input devices are those devices which send data or information to the Central Processing Unit. The main input devices are:

i) KEYBORD: It is used to enter text. It contains alphabetic, numeric and other keys for entering data.
ii) MOUSE:It is a pointing device. It controls the pointer on the screen.
iii) MICROPHON: It is used to enter voice into the computer.
iv) SCANNER: It reads printed text and graphics and then translates the result into digital form.
v) DIGITAL CAMERA:It is used to take photos.
vi) PC CAMERA: It is used to create movie and to take photos on the computer.

2) OUT PUT DEVICES:
A hardware component used to display information to the user output device.

i) MONITER: It is used to display text, graphics and video output.
ii) PRINTER: It is used to display printed output on paper.
iii) SPEAKER:It is used to hear sound to hear sound music and voice outputs.

3) STORAGE DEVICE:
The hardware components used to store data, instructions and information permanently are called storage devices. For example floppy disk drive, zip drive, hard disk drive, CD-ROM drives etc.


4) COMMUNICATION DEVICES:
It is used to communicate and exchange data, instructions and information with other computers. For example Modem.


UNITS OF CPU:

ALU(ARTHMETIC AND LOGICAL UNIT)
ALU is a part of CPU. Actual execution of instructions takes place in this part. All arithmetic and logical operations are performed in ALU. It consists of two units:

1. Arithmetic Unit
It performs basic arithmetic functions such as addition, subtraction, division.

2. Logical Unit
It performs logical operations like comparing two data items to find which data item is greater than, equal to, or less than the other.

CONTROL UNIT
It acts like a supervisor of the computer. It does not execute program instruction by itself. It controls and coordinates all activities of computer system.

Memory Unit (MU)
It is responsible for storage of data and information. The memory unit consists of two types of memory which are RAM and ROM.


Some Important Definitions And Short Notes:

RAM:
RAM stands for random access memory. It is that part of CPU where temporary information is stored.

Byte:
A group of 8 bits is called a byte.

Icons:
Pictorial objects on the desktop or screen are called Icons.

Mouse:
It is an input device, normally called a “Pointing device”. This device is used for pointing anything on monitor through a blinking cursor.

Software:
A set of instructions or codes written in a defined manner or prewritten programs which control the operations of computer.

Control Unit:
A unit of CPU which is responsible for all automatic operations carried out by the digital computers is called CU. The CU directs and coordinates all activities of a computer.

LAN:
LAN stands for local area network. It is privately owned communication network that serves users within a confirmed geographical area. The range is usually within a mile-perhaps one office, one building or a group of buildings.

WAN:
It stands for wide area network. It is a communication network that covers a wide geographical area. The range is usually a state or a country. Examples are Telenet, Uninet etc.

Modem:
Modem is abbreviation of Modulate-de-Modulate. Modulation is a process that converts digital signals into Analog form and Demodulation is a process that converts Analog signals into digital form. The device which performs modulation and demodulation is called a MODEM. In simple words it is a device that converts the digital signals into Analog and then back from Analog to digital form.

ALU:
A unit of CPU that performs arithmetic and logical operations is called ALU.

Register:
Registers are high-speed staging areas that temporarily store data during processing and provide working areas for computation.
Registers are contained in control unit and arithmetic Logic Unit. Following are the major types of registers:
i) Address Register
ii) Instructions Register
iii) Storage Register
iv) Accumulator Register

Soft Copy:
It displays the data on screen of monitor. It can be carried in a floppy disk. A change can be made in a soft copy.

Hard Copy:
The data is printed on paper card etc. with the help of printer. It cannot be carried in a floppy disk. No change can be made in hard copy.
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Energy:


Definition Of Energy:

“Energy is an agent which is responsible to do work.”

OR

“The capacity or ability of doing some work is known as energy.”


Kinds OR Types Of Energy:

i) Kinetic energy: The energy due to motion of a body is called Kinetic Energy.
Example: i) Moving ball can break a glass window ii) A striking hammer can drive a nail.

ii) Potential Energy: the energy which is possessed by a body by means of its position is known as potential energy.

iii) Mechanical Energy: Energy of an object due to its motion or position
OR
A combination of kinetic and potential energy resulting from the force of gravity or the movement or release of a machine component, such as a spring, clamp, or wheel.

iv) Chemical energy: energy in a substance that can be released by a chemical reaction. For example: coal, petroleum are the source of chemical energy.

v) Electrical energy: energy made available by the flow of electric charge through a conductor.

vi) Heat energy: a form of energy that is transferred by a difference in temperature.

vii) Solar energy: Radiant energy emitted by the sun.

viii) Hydropower energy: The energy in flowing water is called Hydropower Energy.

ix) Nuclear energy: The energy released by a nuclear reaction, especially by fission or fusion.

Energy Resources:
Energy resources can be divided into two categories.
1) Renewable Resources Of energy
2) Non-Renewable Resources Of energy

Renewable Resources Of Energy:

Renewable energy is energy which is generated from natural sources i.e. sun, wind, rain, tides and can be generated again and again as and when required. They are available in plenty and by far most the cleanest sources of energy available on this planet. For e.g.: Energy that we receive from the sun can be used to generate electricity. Similarly, energy from wind, geothermal, biomass from plants, tides can be used this form of energy to another form.
OR
The resources of energy which can be used again and again are known as renewable resources. These are:

i) Solar energy: Solar energy is the energy derived from the sun through the form of solar radiation.

ii) Wind energy: Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, wind mills...

iii) Hydropower energy: Energy in water can be harnessed and used. Since water is about 800 times denser than air, even a slow flowing stream of water, or moderate sea swell, can yield considerable amounts of energy.

iv) Tidal energy: Tidal power, also called tidal energy, is a form of hydropower that converts the energy of tides into useful forms of power - mainly electricity.

v) Geothermal energy: Geothermal energy is power extracted from heat stored under the earth’s crust. This power source is generally cost effective, usually reliable, mostly sustainable, and generally environmentally friendly.

Non-Renewable Resources Of Energy:

Renewable energy is energy which is taken from the sources that are available on the earth in limited quantity and will vanish fifty-sixty years from now. Non-renewable sources are not environmental friendly and can have serious effect on our health. They are called non-renewable because they can be re-generated within a short span of time. Non-renewable sources exist in the form of fossil fuels, natural gas, oil and coal.
OR
The resources of energy which can be used for a particular period of time, after that they may not be available for the use of man. These include:

i) Coal: Coal is a combustible black or brownish-black sedimentary rock formed from fossilized plants. Coal consists of amorphous carbon with various organic and some inorganic compounds and is normally occurring in rock strata in layers or veins called coal beds.

ii) Gas: Natural gas is a combustible mixture of hydrocarbon gases that occurs with petroleum deposits consisting primarily of methane. It is found with other fossil fuels and in coal beds and is created by the decay of methanogenic organisms in marshes, bogs, and landfills. Lower temperatures are likely to produce more petroleum, and higher temperatures are likely to produce more natural gas.

iii) Oil: Petroleum, also known as crude oil, is a naturally occurring toxic combustible liquid primarily made up of hydrocarbons. Petroleum is the result of partial decay of living organisms occurring in the rock strata of certain geological formations.

iv) Nuclear fuels: Nuclear power is produced by controlled nuclear fission (splitting atoms). In most cases nuclear power plants use nuclear fission reactions to heat water, using the steam to produce electricity. Uranium, specifically, uranium -235, is one of the few elements easily fissioned.

v) Wood: Wood and wood products used as fuel, including round wood (cord wood), limb wood, wood chips, bark, sawdust, forest residues, charcoal, pulp waste, and spent pulping liquor.
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Short Notes (Energy)


Non-Conventional Sources Of Energy:
Non-conventional sources of energy are those sources of energy which are not in common use at this time but are being considered or explored to bring to routine use in the future. With the exhaustion of conventional sources of energy the search for non-conventional sources of energy have been intensified.
Conventional sources of energy are coal, gas, oil, wood and nuclear fuels. These sources are in routine use nowadays.
Non-conventional sources of energy are solar energy, geothermal energy. Wind energy, tidal energy and ocean thermal gradient.

Solar Energy:
The energy of the sun is called solar energy. It has been estimated that on the average 180,000 kilowatts solar energy is falling per square kilometre of the earth. Solar energy is utilized in two ways.
A solar furnace contains thousands of mirrors to focus the sun rays. In this solar heater produces heat used in industry or houses. The heaters heat up water or air. Solar energy can also be used indirectly. Solar cells made up of panels of semi-conductors (usually silicon) are used which when illuminated by sun generate electricity. These kinds of cells have frequently been used in space probe. They have not become popular in domestic side due to high cost.

Wind Energy:
Energy obtained from wind by using wind mills is called wind energy. The wind rotates generated which produce electricity.
Previously wind mills were used for grinding grains. The rotating wings of a wind mill can be attached to a magnet which gives an electric current with rotation. Low power, high cost and uncertainties of weather had not made power generation through wind power.

Geothermal energy:
Heat energy obtained from the hot molten metals inside the earth crust serves as the source of thermal energy. This type of energy is present in the form of hot water and steam. Geothermal electricity plants change the geothermal energy into electricity. Hot water of springs is being used for power generation particularly in USA, Italy, and Japan etc. furthermore; hot springs are used as geysers for heating the houses.

Nuclear Energy:
The most concentrated form of energy is in the atomic nuclei. This energy can be released by the processes of fission or fusion.
Fusion reactions have been producing electricity in commercial quantities for about 30 years. In Pakistan we have got only one fission nuclear reactor located at Karachi which generates 137 megawatt of power to meet ur future domestic and industrial needs, we will have to generate electricity from nuclear plants using (Uranium U-235) and plutonium s fuel.

Tidal Energy:
Energy which is obtained through the tidal waves of the sea is called tidal energy. Tidal waves of sea strike the shore constantly. These waves are used to run electric generators which produce electricity. The kinetic energy of the tides is also used to produce other forms of mechanical work. Tidal power station traps high tides behind a barrage. The water flows through turbines.
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Greenhouse Effect:


The heating that occurs when gases such as carbon dioxide trap heat escaping from the Earth and radiate it back to the surface; so-called because the gases are transparent to sunlight but not to heat and thus act like the glass in a greenhouse.
OR
The overall warming of the earth's lower atmosphere primarily due to carbon dioxide and water vapour which permit the sun's rays to heat the earth, but then restrict some heat-energy from escaping back into space.

Greenhouse Gases:
i) Carbon dioxide CO2
ii) Methane
iii) Water Vapour
iv) Chloro Fluoro-Carbon (CFC)
v) Nitrous oxide

Mechanism OF Greenhouse Effects:
• Our Earth receives most of its energy, called radiation, from the Sun.
• This energy is electromagnetic radiation in the form of Visible light, with small amounts of Infrared (IR) and Ultraviolet (UV).
• The incoming Visible solar energy has a very short wavelength and passes right through the atmosphere.
• The Earth's surface absorbs the solar energy and releases it back to the atmosphere as Infrared (IR) radiation, some of which goes right back into space.
• But some of the IR radiation emitted by the Earth is absorbed by greenhouse gases in the atmosphere and sent back towards the Earth's surface.
• That warms the Earth's surface. Three main gases in our atmosphere that contribute to the greenhouse effect are carbon dioxide, methane, and water.
• These gases absorb the infrared radiation emitted by the Earth and re-radiate the energy as heat back towards the Earth, causing a warming known as the greenhouse effect.
• The warming due to greenhouse gases is expected to increase as humans add more greenhouse gases to the atmosphere.

Sources Of Greenhouse Gases:
Carbon dioxide (CO2) is a colourless gas that's a by-product of the combustion of organic matter. Today human activities are pumping huge amounts of CO2 into the atmosphere, resulting in an overall increase in carbon dioxide concentrations.

Methane occurs naturally when organic material decomposes. Man-made processes produce methane in several ways:
• By extracting it from coal
• From large herds of livestock (i.e., digestive gases)
• From the bacteria in rice paddies
• Decomposition of garbage in landfills

Importance Of Greenhouse Effect:
Following is the importance of greenhouse effect.
i) Without greenhouse effect, the Earth would not be warm enough for humans to live.
ii) Without greenhouse gases, heat would escape back into space and Earth’s average temperature would be about 600 F colder.
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Global Warming:


A gradual increase in the overall temperature of the earth's atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide, CFCs, and other pollutants

Causes Of Global Warming:
The main causes of global warming, in order of the magnitude of their impact, are:
1. Carbon Dioxide from:
A. Fossil Fuel
B. Deforestation
C. Failing Sinks

2. Methane from:
A. Cattle and Rice Paddies
B. the Arctic Tundra
C. Clathrates

3. Nitrogen Oxides from Farming
4. Other Gases

Effects OF Global Warming:
When it comes to global warming, harmful effects like melting polar ice caps, weather changes, and an increase in diseases are changing the world and will ultimately affect your life. Below is the list of effects that global warming is having on environment, climate and human kind.

1. Melting of glaciers: The melting of glaciers will create plethora of problems for human kind and the animals living in the earth. Due to increased global warming, the level of the sea will rise which will lead to flooding and this will in turn create havoc in human life. Apart from raising the sea levels, it will also endanger several species of animals and thus will hamper the balance of the ecosystem. Moreover these large glaciers reflect light back into the space and with meltdown of these glaciers, earth will be further warmed.

2. Climate Change: Irregular weather patterns have already started showing results. Increased precipitation in the form of rain has already been noticed in polar and sub Polar Regions. More global warming will lead to more evaporation which will cause more rains. Animals and plants cannot easily adapt to increase rainfall. Plants may die due to it and animals may migrate to other areas, which can cause entire ecosystem out of balance.

3. Droughts: Large scale evaporation will be the major cause of droughts in many places particularly Africa. Although, it is reeling under the huge pressure of water crisis, increased global warming would further make the situation worse and will cause malnutrition.

4. Diseases: As the temperature becomes warmer, it will have an effect on the health of humans and the diseases they are exposed to. With the increase in the rainfall, water borne diseases are likely to spread specially malaria. The earth will become warmer and as a result heat waves are likely to increase that will cause a major blow to the people particularly in Europe.

5. Hurricanes frequency: As the temperature of the oceans rises, hurricanes and other storms are likely to become stronger. With the increase in the global warming the water in the ocean warms up and it heats up the surrounding air, creating hurricanes. More water evaporation means more hurricanes.

6. Agriculture: Global warming will affect agriculture. Although the results are not visible yet, but it may show its colours in years to come. As the global temperature will increase plants will find it harder to survive and will die. Plants are the major source of food for human beings and as a result food shortage will occur. The shortage of the food may lead to war and conflicts in some countries.

Steps To Control Global Warming:
i) Use Public Transport:
ii) Use Renewable Energy Like Wind Power:
iii) Burn Methane:
iv) Use Smart Cooler, Heater & Air Conditioner
v) Tune up and maintain vehicles properly
vi) Reduce electricity usage to the maximum
vii) Prefer recycling
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