Thursday, 29 December 2011

National Data about Pakistan




  • Land Area - 796,095 square km (307,374 sq miles)

  • Major Physical Features – Highest point : K2 - 8,611m (28,250Feet)

  • Population (1994)- 128,856,000

  • Form of government- Federal multiparty republic with two legislatives houses.

  • Armed Forces    – Army     : 520,000
                                 Navy    : 22,000
                                 Air Force : 45,000

·         Largest Cities     Karachi     (5,181,000)
                                      Lahore      (2,953,000)
                                      Faisalabad (1,104,000)
                                      Rawal Pindi(5,181,000)
                                     Multan       (722,000)
                                     Islambad    (204,000)

·         Official Language      : Urdu, English

·         Official Region           : Islam

·         Currency                   : 1 Pakistan Rupee-100 paisa

·         Gross National Product (per capita 1993): us $ 430

·         Gross Domestic Product ( 1993): US $ 46.360 MILLION

·         Life expectancy at birth :Male -56.8 year  Female- 58.0 year   

Tuesday, 18 October 2011

Know about Acid Rain..


The term acid rain refers to what scientists call acid deposition.  It is caused by airborne acidic pollutants and has highly destructive results.


Scientists first discovered acid rain in 1852, when the English chemist Robert Agnus invented the term.  From then until now, acid rain has been an issue of intense debate among scientists and policy makers.


Acid rain, one of the most important environmental problems of all, cannot be seen.  The invisible gases that cause acid rain usually come from automobiles or coal-burning power plants.

Acid rain moves easily, affecting locations far beyond those that let out the pollution.  As a result, this global pollution issue causes great debates between countries that fight over polluting each other's environments.


For years, science studied the true causes of acid rain.  Some scientists concluded that human production was primarily responsible, while others cited natural causes as well.  Recently, more intensive research has been done so that countries have the information they need to prevent acid rain and its dangerous effects.


The levels of acid rain vary from region to region.  In Third World nations without pollution restrictions, acid rain tends to be very high.  In Eastern Europe, China, and the Soviet Union, acid rain levels have also risen greatly.  However, because acid rain can move about so easily, the problem is definitely a global one.

Thursday, 16 June 2011

Physical properties of Metals



The physical properties of metals can be easily explained in terms of this "electron sea" model of metallic bonding. Characteristic physical properties of metals include:
  • Metals are ductile (they can be drawn into wires) and metals are malleable (they can be pounded into thin sheets)
  • Metals have relatively high melting points and remain in the liquid state over a wide temperature range.
  • The transition metals have higher melting points than main group metals (those in Group IA and IIA). The lanthanons and actinons also have higher melting points than the metals in Group IA and IIA.
  • Metals have varying degrees of hardness.
  • Metals conduct electricity and heat.
  • Metals are usually shiny. They have luster.

Global Warming


What is Global Warming??

Global warming is when the earth heats up (the temperature rises).  It happens when greenhouse gases (carbon dioxide, water vapor, nitrous oxide, and methane) trap heat and light from the sun in the earth’s atmosphere, which increases the temperature.  This hurts many people, animals, and plants.  Many cannot take the change, so they die.

What is Green House Effect??

The greenhouse effect is when the temperature rises because the sun’s heat and light is trapped in the earth’s atmosphere.  This is like when heat is trapped in a car. On a very hot day, the car gets hotter when it is out in the parking lot.  This is because the heat and light from the sun can get into the car, by going through the windows, but it can’t get back out.  This is what the greenhouse effect does to the earth.  The heat and light can get through the atmosphere, but it can’t get out.  As a result, the temperature rises.



Importance of Water


Water is our lifeline that bathes us and feeds us. In ancient cultures water represented the very essence of life. The Romans were the first to pipe water into their growing cities, especially with their aqueducts. They also realized that sewage water could cause damage to their people, and needed to be removed from large areas of people.
Water has played a role not only in the history of countries, but in religion, mythology, and art. Water in many religions cleanses the soul through holy water. For example, the water at Lourdes, France is thought by many religions to be sacred water with healing powers. In Egyptian mythology, the Nu was the beginning of everything and represented water. It brought life to their people, but in drought, produced chaos.
Water has always been perceived as a gift from the gods as it rained from the heavens.
The water or hydrologic cycle explains interactions between the atmosphere, hydrosphere, and lithosphere. The water or hydrologic cycle is a major driving force on our planet. Water is in constant motion, evaporating into the atmosphere from oceans, lakes, rivers and streams. When the atmosphere can no longer support the moisture within the clouds, we experience rain, snow, hail, or sleet. Some water is locked in the form of ice at the polar caps and in glaciers. Water melts in the spring, producing runoff, that percolates through the Earth as groundwater (subsurface) or makes its way back to the sea (surface). The oceans contain most of the water, but it is salt water which is unusable by most organisms. Only pure H2O (water) can interact with organisms.
The movement of the oceans also has a direct effect on the atmosphere. The atmosphere is that envelope of gas that keeps organisms living on this planet. Oceans and atmosphere interact to give us weather.
Water provides the Earth with the capacity of supporting life. An organism doesn’t have to be told how important water is to their existence. An amphibian knows to lay their eggs in water or else there will be no new born. Even flies know to lay their eggs in fresh water.
The only organism that doesn’t understand the importance of water is humans, especially in industrialized countries. Children in those societies turn on the water in a sink and never think about the trouble someone has gone for that "miracle" to occur.
In the United States it is mandated by law that its citizens should be given clean and abundant water. Dams, reservoirs, filtering plants, and pipes all bring clean water when the facet is turned on. Sewage water is only mixed with recycled water supplies after the water goes through rigorous cleaning methods. Water borne diseases do not effect the U.S. population like in other countries that do not treat their water supply.
Schistosomiasis worms, parasite in water.
Water borne diseases are any illnesses caused by drinking contaminated water. Diseases can include infection from bacteria (Salmonella), viruses, or by small parasites (Cryptosporida, Giardia, and Toxoplasma). These organisms and viruses cause diseases like cholera, typhoid fever, malaria, botulism, polio, dysentery, giardia, and hepatitis A. One of the first symptoms of these diseases is diarrhea, which cause about three million deaths throughout the world, mainly in India, Africa, and South America.
Sewage is sometimes discharged into rivers, where children downstream might be taking a bath or using the water to drink. The simplest treatment method is boiling. Just bring the water to a boil for at least one minute, then allow it to cool. But this is not always effective in heavily chemical polluted water supplies.
Without water, organisms could not exist. Water is a resource that should not be taken for granted. It needs to be conserved, just as we save other valuable resources.
Water is one of the weirdest compounds known to humans. The difference between the boiling point and freezing point of water is one of the largest ranges of any compound. It is this span of temperature that mirrors the range of where life can exist, from bacteria to humans. Water also has a very high specific heat, which means that it can absorb or lose much heat before its temperature changes. This is important in maintaining body heat in mammals. It also takes a lot of energy before vaporization can occur. For this reason, water evaporates slowly from ponds and lakes, where many life forms are dependent on a stable, warm environment.
Water is less dense in its solid state than in its liquid state, so that ice floats instead of sinking. This property permits life to develop in polar and subpolar regions where ice floats and allows life to continue living below the surface. If ice were heavier than water, it would sink, and more ice would form on top of it. As a result, all life in the waters would be trapped in the ice in the many areas of the world where it gets cold enough to freeze water.
Water is a remarkable solvent, where most elements and compounds can dissolve in its powerful molecular structure. Gases such as oxygen and carbon dioxide, can also dissolve, making it readily available for photosynthetic and nonphotosynthetic organisms to use.
Resistance of water to a disturbance.
Water also exhibits viscosity. One can observe the effects of viscosity alongside a stream or river with uniform banks. The water along the banks is nearly still, while the current in the center may be swift. This resistance between the layers is called viscosity. This property allows smaller fish to live near the shore, while larger fish are able to swim efficiently in strong currents. Viscosity is also responsible for the formation of eddies, creating turbulence that leads to good mixing of air in the water and more uniform distribution of microscopic organisms.
How water provides all these properties are complex, but only emphasizes the importance of water to every organism on Earth.

Facts about Mount Everest


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  • Tallest mountain in the world.
  • Number of people to attempt to climb Mt. Everest: approximately 4,000.
  • Number of people to successfully climb Mt. Everest: 660.
  • Number of people who have died trying to climb Mt. Everest: 142.
  • Height: 29,028 feet, or 5 and a half miles above sea level. This is equivalent to the size of almost   20 Empire State Buildings.
  • Location: part of the Himalaya mountain range; straddles border of Nepal and Tibet.
  • Named for: Sir George Everest, a British surveyor-general of India.
  • Age: approximately 60 million years old.
  • Other names: called "Chomolungma" by Tibetans and Sherpas, which means "Mother Goddess of the Earth."
  • Countries visible from the summit: Tibet, India, and Nepal.
  • First to climb to summit: Edmund Hillary and Tenzing Norgay on May 29, 1953.
  • Notable dates:
    1921 — Dalai Lama allows British reconnaissance party to visit Tibet and the northern side of Mt. Everest.
    1924 — British explorers George Mallory and Andrew Irvine disappear near the summit, along the Northeast Ridge. It is possible that they may have actually been the first to reach the summit, but they never returned.
    1949 — Nepal opens its borders, making access to the mountain's southern peak possible.
    1953 — Hillary and Norgay reach summit.
    1963 — First Americans reach the summit.
    1989 — First two women, both American, reach the summit.
    1990 — Sir Edmund Hillary's son, Peter, reaches summit.
    1996 — Eleven people die during spring expeditions.
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