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					                   2010-2011 оны хичээлийн жилийн намрын улиралд төгсөх
               ШУТИС ийн магистрантын англи хэлний шалгалтанд өгөх чиглэл

                      Шалгалт авах хугацаа: 2010 оны 11-р сарын 20-ний өдөр

                                                                           10:00-тест

                                                                           13:00-аман шалгалт

                      English Proficiency Exam for Master Students

The following 30 texts are for the master students who are giving English Exam. The texts
followed by reading comprehension and vocabulary exercises.

Also there are another 30 texts for translation and speaking tasks will be added (60% of the
grade). The grammar test in the exam will be 40% of the total grade. Total grade is 100%.

Texts:
1. Cells
2. Microscopic Organisms
3. Energy
4. Atoms
5. Global Warming Blamed For Increase in Natural Disasters
6. How does a computer work?
7. Robotics of Micros and Nanos
8. Computer Viruses
9. Artificial intelligence
10. The Physical and Chemical Basis of Life
11. Migration in the 19th century
12. Information Technology
13. All about Metals
14. Sleep and Emotions
15. Computer Reads X-ray
16. How is Waste Recycled?
17. Work and Energy
18. Supplying Energy
19. Vitamin
20. Acupuncture
21. Silver, the Magic Metal
22. The hidden world of science
23. The solar system
24. The water merry-go-round
25. Gemstone
26. Engineer
27. Why do Earthquakes Happen?
28. The discovery of the X-ray
29. Scientific knowledge
30. Can computer think?



Text 1

                                          Cells

Cells are the smallest part (unit) of life. It was discovered by Robert Hooke and is the functional
unit of all known living organisms. It is the smallest unit of life that is classified as a living thing,
and is often called the building block of life. Some organisms, such as most bacteria, are
unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. Humans
have about 100 trillion or 1014 cells; a typical cell size is 10 mm and a typical cell mass is 1
nanogram. The largest cells are about 135 µm in the anterior horn in the spinal cord while
granule cells in the cerebellum, the smallest, can be some 4 µm and the longest cell can reach
from the toe to the lower brain stem (Pseudounipolar cells). The largest known cells are
unfertilised ostrich egg cells which weigh 3.3 pounds.

All living things are made of cells, and all cells have the same parts: nuclear, cytoplasm, and membrane.
The nucleus is the center of the cell. It contains the chromosomes and the genes. The genes carry the
information that tells the cell what to do. Chromosomes and genes help to make new cells. The cytoplasm
surrounds the nucleus in the cell. It contains several different things. Different kind of cells have different
things in their cytoplasm. The cell membrane is around the cell. The membrane controls the flow of
liquids in and out of the cell.

Plant cells are different from animal cells. In addition to the nucleus, cytoplasm, and membrane, they
contain a cell wall, vacuoles, and chloroplasts. The cell wall is around the membrane. It is made of
cellulose, and it is not living. It gives plant cells a shape like a box. Vacuoles are round structures in the
cytoplasm. A membrane surrounds them, and they contain water and other things. The cell uses the
vacuoles to store things. They sometimes contain pigments. These pigments give flower cells their colors.
Chloroplasts are also in the cytoplasm. They contain a green pigment, chlorophyll, and they make food
for the plant. Chloroplasts are necessary for photosynthesis.

In 1835, before the final cell theory was developed, Jan Evangelista Purkyne observed small
"granules" while looking at the plant tissue through a microscope. The cell theory, first
developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms
are composed of one or more cells, that all cells come from preexisting cells, that vital functions
of an organism occur within cells, and that all cells contain the hereditary information necessary
for regulating cell functions and for transmitting information to the next generation of cells.

The word cell comes from the Latin cellula, meaning, a small room. The descriptive term for the
smallest living biological structure was coined by Robert Hooke in a book he published in 1665
when he compared the cork cells he saw through his microscope to the small rooms monks lived
in.

Text 2
                                      Microscopic Organisms

In the seventeenth century, Antonie van Leeuwenhoek was the first person to see tiny organisms
with a microscope. He called them animalcules. Later, scientists in the eighteenth and nineteenth
centuries named these animalcules bacteria and protozoa. This was the beginning of the sciences
of the bacteriology and protozoology, the studies of microscopic organisms. Bacteriologists and
protozoologists have studied these organisms for many years, but it is difficult to classify them.

Scientists cannot classify some of these microscopic organisms in the plant of animal kingdom,
so they put them into another kingdom, protist. Some protists are like animals. They do not have
chlorophyll, and they cannot make their own food. These protists get their food from other
organisms.

Other protists are like plants. They have chlorophyll, and they can make their own food. They
usually live in water. Both animal and plantlike protists provide food for other plants and animals
that live in the water. Many protists are single-celled organisms. They have only one cell. Others,
however, are multi-celled. They have many cells. Because these organisms are neither plants nor
animals, scientists put them in another kingdom.

Bacteria are also difficult to classify in the plant or animal kingdoms. They have only one cell,
but the cells does not have a nucleus. It contains only a cell membrane and cell wall. Bacteria
cannot make their own food. They must get the food from other organisms. Some bacteriologists
classify bacteria separately in the monera kingdom.

Another microscopic organism is the virus. It is much smaller than protists or bacteria. Scientists
can see it only with the electron-microscope. A virus is not a cell. It is smaller than a cell. It does
not have a cytoplasm or a nucleus. It has a cover of protein, and inside the protein, there is
reproductive material. This reproductive material helps the virus reproduce. It makes more
viruses.

The virus reproduces only when it is inside another cell. When it enters another cell, it begins to
reproduce. It makes more and more viruses inside the cell until the cell breaks open and the
viruses go into other cells. For this reason, scientists have difficulty classifying it as living or
nonliving. Outside another cell, the virus is inactive. It does not become active and reproduce
until it enters another cell.

Although we cannot see them, microscopic organisms are everywhere. They are an important
part of life on the earth. It is difficult to classify these organisms, because they are different from
other plants and animals. Some of them have chlorophyll like plants, and others do not. Some of
them are not complete cells. Bacteria do not have a nucleus, and viruses do not have cytoplasm.
To help classify microscopic organisms, some bacteriologists have added two more kingdoms:
the protists and the monera.
Text 3

                                             Energy

The word energy has different uses. In the sentence “Young people have more energy than old
people,” it means strength, power, and activity. In physics, energy is a very important idea. It is
the ability to do work, and it has two forms.

In physics there are two forms of energy: kinetic and potential. Kinetic energy is movement or
motion. A moving car has kinetic energy. If it hits another car, it will damage the other car. The
amount of kinetic energy depends on the size and speed of the car. A truck can do more damage
than a bicycle, and a car going 50mph can do more damage than a car going 5mph.

The formula KE = 1/2mv² represents kinetic energy. In other words, kinetic energy is one-half of
the object‟s mass(size) multiplied by its velocity(speed) squared.

Potential energy is the energy inside something. Wood has potential energy. Oxygen(O) has
potential energy. Burning the wood releases, or lets out, the energy. Processes that release energy
are exothermic processes. Processes that absorb energy are endothermic process. The total
energyof an object is the sum of its potential and kinetic energy.

The amount of total energy in the universe is constant. The amount of energy does not change.
There is no new energy. No energy is lost. This is the law of conservation of energy. There is
never more energy, and there is never less energy.

Energy does change, however. It can change from one form to another. This process is
transformation of energy. Energy may change from water to electricity. Light, sound, electricity,
and heat are ways to transmit energy.

Most of the world‟s energy comes from the sun. Plants produce food for energy during
photosynthesis. The sun‟s energy in wood, oil, and other things that people use for energy.

People use many sources of energy. Ancient people used only their arms, hands, and simple tools
until they discovered fire. Later, people learned to use the energy of the wind to sail ships. Then
they learned to use animals to do work. In the eighteenth and nineteenth centuries, people began
to use machines. The first machines used steam. They burned coal to heat water. The hot water
turned into steam, and the steam engine did the work. Later, people began to use the gasoline
engine, and today people are using nuclear energy. There are many sources of energy.

Energy is one of the basic concepts, or ideas, or physics. It is the ability to do work. There are
two forms of energy and two important laws that explain energy. Without energy we could not
live. We need energy to work, and scientists are always looking for new sources of energy.
Text 4

                                             Atoms

Energy and matter are the two basic ideas in physics. Anything that takes up space and has
weight is matter. It can be solid, liquid, or gas. For example, ice is solid, water is liquid, and
vapor is gas. Matter must have both volume and weight. Light and heat do not have weight, so
they are not matter; they are energy. Matter is everywhere around us. Scientists study matter and
divide it into smaller and smaller parts.

The smaller parts that scientists divide matter into are called molecules. A molecule is the
smallest part of something that is itself. For example, a molecule of water (H₂O) is two parts
hydrogen and one part oxygen. A molecule is the smallest part of water. Hydrogen and oxygen
alone are not water.

Scientists divide molecules into smaller parts. These smaller parts are atoms A sugar molecule
contains three different kind of atoms. One molecule of sugar has twelve carbon (C) atoms,
twenty two hydrogen (H) atoms, and eleven oxygen (O) atoms. Atoms are small pieces of matter.
At present, scientists know about 100 different kinds of atoms in the world. These 100 atoms
combine in different ways to make all matter in the world.

The ten most common kinds of atoms in the world are oxygen (O), silicon (Si), aluminum (Al),
iron (Fe), calcium (Ca), sodium (Na), potassium (K), and magnesium (Mg). These are elements.
Atoms of different elements combine to make compounds. A compound consists of different
elements.

Atoms are very tiny. Scientists can see them with an electron microscope, and they study atoms
in other ways too. An atom has two main parts: the nucleus and electrons. The nucleus is the
center of the atom. Electrons are tiny parts that go around the nucleus. The nucleus also has two
parts: protons and neutrons. There are the same number of protons in the nucleus as there are
electrons in the atom. Electrons, protons, and neutrons, then, are three parts of an atom.

Parts of the atom have electrical charges. Protons have a positive (+) electrical charge; neutrons
have no electrical charge; and electrons have a negative (-) charge. In an atom, there are same
number of protons and electrons. Therefore, the positive protons balance the negative electrons,
and an atom is electrically neutral.

All atoms contain protons, neutrons, and electrons. Different atoms have different numbers of
these particles. For example, aluminum has thirteen electrons, thirteen protons, and fourteen
neutrons. Iron has twenty-six protons, twenty-six electrons and thirty neutrons.

Scientists divide matter into its smallest parts. Atoms are small parts of matter. They are made up
of electrons, protons, and neutrons. Scientists study atoms to learn more about matter.
Text 5

               Global Warming Blamed For Increase in Natural Disasters

The International Federation of Red Cross is blaming global warming for an increase in natural
disasters around the world. In its annual World Disasters Report, the Red Cross says people in
poorer countries are particularly affected by the disasters.

Last year, the Red Cross report says, a record 256 million people were affected by natural
disasters. Over the past decade, according to the report, natural disasters have killed 750,000
people.

While the number of earthquakes and volcanic eruptions has remained steady over the past
decade, what the report refers to has hydro-meteorological disasters – floods, droughts and
hurricanes – have increased dramatically.

The head of Red Cross Operations in Africa and Middle East, Roger Bracke, says the agency
believes these increases are related to global warming.

Roger Bracke: We see total abnormal patterns, repetition of Floods in areas where we have seen
those less frequently. We also see massive droughts – India … Tajikistan … Uzbekistan … - on
a much larger scale than we have seen before. The frequency and extent of the problem have no
other explanation today than global warming.

The report says people in poorer areas, because they lack resources, are usually the ones who
suffer the most after a natural disaster strikes. Red Cross senior officer Sean Deely says any aid
program to disaster-stricken areas should include ways of helping people rebuild their lives.
Ignoring economic realities, Mr. Deely says, puts people at greater risk from future disasters.

Mr. Deely: What we really need to do is have the flexibility to take a longer-term approach to
programming, a longer-term approach that focuses on rebuilding livelihoods and focuses on
building and reinforcing local economies, so that people and communities not only have the
capacity to resist disaster and the consequences of disaster, but have the capacities and resources
to rebuild their lives afterwards.

The Red Cross acknowledges that there is a limit to what the humanitarian world can do to help
victims of natural disasters. If these phenomena continue to increase, if fear humanitarian
agencies will no longer able to help all people in need.

Text 6

                                  How does a computer work?

Uniquely characteristic of computers is their almost unbelievable speed and complexity. In
principle, though, the work they do can be divided into three basic steps. First, data or
information is input or fed into the computer. The machine then processes or manipulates this
data. The final step is the output or displayed result of this processed information. Software is the
term used for the data and programs, the „‟soft‟‟ or intangible elements of the system. Data refers
to the actual information (numbers, words, images etc.) the computer is to process while
programs consists of the instructions on how to process that information. The “hard” or
mechanical and electronics parts of a computer system are called hardware. Basically, the
hardware of a computer system consists of three main parts: the central processing unit (usually
shortened to CPU), the main memory and the extra devices, known as peripherals.

As its name implies, the CPU plays a central role which is why it is also often referred to as the
“brain” of the computer. It has the double function of executing or carrying out the program
instructions while also coordinating all the other activities of the system. It consists of three main
parts: the control unit, the arithmetic logic unit (ALU) and the registers. It is the job of the
control unit to examine and interpret a given program‟s instructions, activating the different parts
of the computer to carry out their various functions. The ALU is responsible for performing
mathematics calculations and logical operations. Register‟s are special, high-speed memory units
to store and control data. Two main types are the program counter (PC) which registers the next
instruction register (IR) which contains the current instruction.

The main memory contains and the data and programs the CPU is currently processing or which
are waiting to be processed. It is characterized as volatile, meaning that the data is lost once you
switch off the computer. In contrast non-volatile storage devices such as floppy, hard or optical
disks retain their data and are used to permanently store both data and programs. The collective
name for the permanent storage devices as well as the vast array of input/output devices is
peripherals. They are generally connected to the CPU by plugging into one of the appropriate
ports on the rear panel of the computer and have a wide variety of functions. We refer to the
configuration of a computer system when talking about all its main physical units, i.e. its CPU,
main memory and any number and kind of peripherals.

Text 7

                                    Robotics of Micros and Nanos

1. For example, a replica of a human hand just a few millimeters across could be attached to an
   endoscope and inserted into a patient. Wearing a virtual reality glove, the doctor would not
   only be able to see but also “feel” inside the patient. Other scientists are creating microscopic
   insects that can actually fly. They could be used to pollinate flowers and to kill real insect
   pests which threaten to destroy crops.
2. Not that researchers are letting such considerations put a damper on their imagination.
   Before the currently is half over, enthusiasts are claiming, we will building machines so tiny
   they will be the century is half over, enthusiasts are claiming, we will be building machines
   so tiny they will be measured in nanometers (= a billionth of a metre). Natobats, atom by
   atom, will build raw minerals or whole houses, clean up toxic waste or, being the size of
   human cells, break down the cholesterol in our blood streams-or so the technology‟s
   proponents claim.
3. Many people are convinced that micro-machines will be the technological future. Using
   silicon chip-making processes it‟s already possible to create miniscule motors with
   mechanical moving parts, barely visible to the naked eye. These tiny micro machines are
   often smaller than the size of a rice grain.
   4. But are micro-machines simply million dollar lab toys are some skeptics claim? Or will
        they one day serve a practical purpose? Their earliest application is foreseen in the field
        of medicine as microsurgical instruments.
   5. It‟s not all clear sailing ahead for micro-technology, however. Engineers are discovering
        the laws of physics don‟t seem to apply in the same degree as devices shrink, mass and
        weight can practical be ignored, while surface tension and function are critical factors.
   6. Even more astonishing are the new Micro-Electro-Mechanical-Systems (MEMS) which
        enthusiasts are predicting will someday be as common as the chip is today. These devices
        are able to pack electronic circuits and moving machine parts into a single microscopic
        silicon package using lithographic processes.

       Text 8
                                          Computer Viruses

       1. Analogous to biological viruses, a computer virus is a program that searches out and
           “infects” other programs. It does this by embedding a copy of itself in the boot sector
           of a disk or in other widely used programs such as spread-sheets or database software.
           The virus itself is executed when an infected file is activated or when the computer is
           started from an infected disk.
       2. Viruses are increasing at an enormous rate. Though there was only one known virus
            In 1986, only four short years later they were being discovered at the rate of one per
       week.        Today computer virus are on the rise with up to 15 new viruses found daily
       and annual growth rates of more than 100%. Naturally, an increase in the number of
       viruses in the computer world has led to a rapid spread in the rate of infections and the
       number of affected computers.
       3. Viruses cannot infect other computers without assistance. While disks used to be the
           major source of infection, email attachments are now the bigger headache and, to a
           large extent, responsible for the sharp rise in infection rates. As opposed to disks
           which are typical for boot-sector viruses, attachments are primarily responsible for
           the spread of macro viruses.
       4. What exactly do computer viruses do? Some are relatively benign and may result in
           nothing worse than “funny” messages or graphics popping up unexpectedly. Others
           are anything but harmless and can cause extensive damage, wasting time, money and
           countless hours of manpower.
5.       Particularly malignant viruses can delete or block access to a user‟s files or
         otherwise cause major damage to software. Virus hoaxes pretending to warn other
         users of some dangerous virus on the loose, are almost as bad. They jam email
         networks and lead to lost productivity and downtime.
6.       Understandably, people tend to react emotionally when threatened with the loss of
         files. It is important, therefore, to keep in mind a few points that counter the
         general myth building and media sensation surrounding viruses. Viruses don‟t
         infect either write protected disks or compressed files. With the exception of
         special types of hardware such as flash memory, they can‟t infect hardware.
7.       Computer viruses can and do cause damage and require effective
         countermeasures. Producing and selling anti-virus software has become a
         lucrative business. Virus scanning and detecting can be done at intervals or each
         time a file is downloaded. With the spread of macro viruses via the internet,
         scanning email attachments is also an important preventive measure.




Text 9
                                    Artificial intelligence
For years there have been endless articles stating that scientists are on the verge of
achieving artificial intelligence that it is just around the corner. The truth is that it may be
just around the corner, but they have not yet found the right block.
 Artificial intelligence aims to build machines that can think. One immediate problem is
to define thought, which is harder than you might think. The specialists in the field of
artificial intelligence complain, with some justification, that anything that their machines
do is dismissed as not being thought. For example, computers can now play very, very
good chess. They can‟t beat the greatest players in the world, but they can beat just
about anybody else. If a human being played chess at this level, he or she would certainly
be considered smart. Why not a machine? The answer is that the machine doesn‟t do
anything clever in playing chess. It uses its blinding speed to do a brute –force
search of all possible moves for several moves ahead, evaluates the outcomes and picks
the best. Humans don‟t play chess that way. They see patterns, which computers do
not.
 This wooden approach to thought characterizes machines intelligence. Computers have
no judgment, no flexibility, and no common sense. So-called expert systems, one of the
hottest areas in artificial intelligence, aim to mimic the reasoning processes of human
experts in a limited field, such as medical diagnosis or weather forecasting. There may
be limited commercial applications for this sort of thing, but there is no way to make a
machine that can think about anything under the sun, which a teen-ager can do.
 The hallmark of artificial intelligence to date is that if a problem is severely restricted, a
machine can achieve limited success. But when the problem is expanded to a realistic
one, computers fall flat on their display screens. For example, machines can understand a
few words spoken individually by a speaker that they have been trained to hear. They
cannot understand continuous speech using an unlimited vocabulary spoken by just
speaker.


Text 10
                         The Physical and Chemical Basis of Life
Most biologists are agreed that all the varied phenomena of life are ultimately explainable
in terms of the same physical and chemical principles which define nonliving systems. It
naturally follows that when enough is known of the chemistry and physics of vital
phenomena it may be possible to synthesize living matter. An opposite view, widely held
by biologist until the present century, stated that some unique force, not explainable in
terms of physics and chemistry, is associated with and controls life. Many of the
phenomena that appeared to be so mysterious when first discovered have subsequently
proved to be understandable without requesting a unique life force, and it is reasonable to
suppose that future research will show that that aspects of life can also be explained by
physical and chemical principles.
To differentiate the living from the nonliving and then to separate living into plants and
animals are difficult to do sharply and clearly. Organisms such as cats and dogs are
clearly recognizable as animals but sponges, for examples, were considered to be plants
until well into the nineteenth century, and there are single-celled organisms which, even
today, are called animals by zoologists and plants by botanists. Even the line between
living and nonliving is rather difficult to draw, for the viruses, too small to be seen with
an ordinary light microscope, can be considered either the simplest living things or very
complex, but nonliving, organic chemicals.
All living things have, to a greater or lesser degree, the properties of specific
organization. Each kind of living organism is recognized by its characteristic form and
appearance the adult organism usually has a characteristic size. Nonliving things
generally have much more variable shapes and sizes. Living things are not homogeneous,
but are made of different parts, each with special functions, thus the bodies of animals
and plants are characterized by a specific, complex organization. The structural and
functional unit of both animals and plants is the cell. It is the simplest bit of living matter
that can exist independently and exhibit all the characterists of life.
       Text 11
                                     Migration in the 19th century
       Between 1815 and 1914, the world witnessed the greatest peaceful migration in its
       history: 35 million people, mostly Europeans, left their homelands to art new lives in
       America. Why did these people risk everything be leaving their homes and families to see
       what the New World had to offer? There are both push and pull factors which we should
       consider. First, what forced emigrants to make the decision to leave? One major cause of
       the exodus among European peasants was the rise in population which in turn led to land
       hunger. Another was politics. Nationalism saw increased taxation and the growth of
       armies, and many young men fled Europe to avoid being conscripted. Also, the failure of
       the liberal revolutions in Europe caused the departure of hundreds of thousands of
       refugees. Physical hunger provided another pressing reason. Between 1845 and 1848,
       the terrible potato famine in Ireland ended in the deaths of one million Irish people and
       the emigration of a further million who wished to escape starvation. Religion also
       encouraged millions to leave the Old World.
          In short, people chose to leave their homes for social, economic and religious reasons.
       As a result, by 1890 among a total population of 63 million, there were more than nine
       million foreign-born Americans. But what were the attractions? First o all, there was the
       promise of land which was so scarce in Europe. Next, factories were calling out for
       labour, and pay and conditions were much better than back home. Men were needed to
       open up the West and build the long railroads, and settlers were needed to populate new
       towns and develop commerce. There was the space for religious communities to practice
       their faith in peace and comparative isolation. As we know, there were losers. To start
       with there were those unwilling immigrants‟, the slaves who had been used as a source of
       cheap labour for the tobacco plantations of the South Nor should we forget the equally
       awful fate of the American Indians. By 1860 there were 27 million free whites, four
       million slaves and a mere 488,000 free blacks.

           Text 12
                                     Information technology

1982 was the year of information technology in Great Britain. But what exactly is infotech?
85% of people polled recently had not a clue what is meant, although 53% of those polled said
they thought it sounded pretty important. They were right. It is. So what is it? Well, it is the
“marrying-up” of products from several key industries: computers, telephones, television,
satellites. It means using micro-electronics, telecommunication networks, and fibre optics to help
produce, store, obtain and send information by way of words, numbers, pictures and sound more
quickly and efficiently than ever before.

The impact infotech is having and is going to have on our lives and work is tremendous. It is
already linking the skills of the space industry with those of cable television so programmes can
be beamed directly into our homes from all over the world. Armies of “steel collar” workers, the
robots, will soon be working in factories doing the boring, complex and unpleasant jobs which
are at present still done by man. In some areas such as the car industry this has already started.
Today, we can use infotech in the different parts of the life. Television is used to enable
customers to shop from comfort of their homes by simply ordering via the TV screen, payment
being made by direct debit of their credit cards. Home banking and the automatic booking of
tickets are also done through the television screen. Cable television which in many countries now
gives a choice of dozens of channels is used to protect our homes by operating burglar and fire
alarms linked to police and fire stations. Computers run our homes, controlling the heating, air
conditioning and cooking systems. The postman was a thing of the past and instead of the postal
service and letters, the electronic mail is received via viewdata screens.

Infotech is the part of the technological revolution and that is with us now.

Text 13

                                               All about metals

Do you know how many different metals are used to build an airplane? There are three main
metals. Aluminum is needed to make the body of the airplane. A special, strong metal called
titanium is used to build parts of the airplane‟s engines. Hundreds of feet (meters) of copper
wire connect all the electrical parts of the airplane.

Where do these different metals come from? They are all found in the earth‟s crust, either as
pieces of pure metal or in minerals that make up ores. Metals can be mixed together to make a
new substance called an alloy. For example, bronze is an alloy of copper and tin.

Metals for different jobs

Some metals are hard and strong but they snap easily. These metals are brittle. Iron is an
example of a brittle metal. Iron is often alloyed (combined) with carbon and manganese to
make steel. Steel is a hard and strong alloy use to make bridges, railway lines and buildings.

It is easy to work with certain metals, like gold, because you can hammer or roll them into
shapes, or stretch them and they won‟t break. Some metals, like sodium, are soft, and others, like
mercury, are liquid.

Tin is an element that comes from the ore cassiterite. It is easy to bend but it is difficult to
corrode or wear away. Tin is used to join, or solder, metals together. Some cans are made from
steel with a thin coating of tin to keep them from rusting. Cans containing soft drinks are made
of light weight aluminum.

Precious metal
We sometimes call valuable metals, such as platinum and gold, precious metals. Platinum is
the most valuable metal in the world. It is called a catalyst because it produces a chemical
reaction in other substances without itself changing. Platinum is more expensive than gold and is
used in many industries. Another metal is iridum. It is often used as a hardening agent for
platinum.

Gold is the third most valuable metal after and iridum. It can be rolled and stretched more than
any other metal. Gold is used to make jewelry and some electronic equipment. Copper is often
added to gold to make it harder.

Another precious metal is silver, which loses its shine, or luster, when exposed to the air. Silver
must be polished to remove any stains. The photographic film in your camera contains silver,
and many ornament and pieces of jewelry are made of silver.

Text 14

                                            Sleep and Emotions

Ninety-five percent of adult Americans average seven to eight hours a night. The rest seem to
need more than nine hours, or get along nicely on less than six. What distinguishes the long and
short sleepers from the majority? To get some answers, psychiatrist Ernest Hartmann advertised
for long and short sleepers to engage in an eight-night “sleep-in” at his laboratory.

His findings indicate that such people differ from ordinary sleepers – and each other – not so
much physically as psychologically. For them sleep serves varying, sometimes surprising
purposes.

Testing showed significant psychological differences between long and short sleepers. The short
sleepers tended to be emotionally stable. Their entire lifestyle involved keeping busy and
avoiding psychological problems rather than facing them. They also seldom woke up during the
night arose in the morning full of energy. Long sleepers, in contrast, checked out as being shy
and somewhat withdrawn. They slept fitfully, woke often and typically got up a bit anxious.

Hartmann discovered that long, short and average sleepers all spend about the same amount of
time in what researchers call “slow-wave sleep”, the deep and relatively dreamless state, totaling
some 75 minutes a night, when people are supposed to get their real recovery from the activities
of the previous day. Additionally, Hartmann concluded that long sleepers spent nearly twice as
much as others in REM (rapid eye movement) sleep – a state in which the sleeper‟s brain is as
active as in full consciousness. REM sleep is dream sleep. Since the long sleeper shows more
symptoms of emotional problems than the short sleeper, who resolutely avoids his problems
anyway.

Text 15
                                        Computer reads X-Ray

       A computer is an electronic device, which executes software programs. Computers have
       become indispensable in today‟s world. Computers play a key role in almost every sphere
       of life. For example, computers play important role in medicine.

       Computers are the excellent means for storage of patient related data. Big hospitals
       employ computer systems to maintain patient records. It is often necessary to maintain
       detailed records of the medical history of patients. Doctors often require the information
       about a patient‟s family history, physical ailments, already diagnosed diseases and
       prescribed medicines. This information can be effectively stored in a computer database.

       Nowadays to diagnose diseases by X-Rays are used widely in medical practice.

       X-Rays have been remarkably effective diagnostic tools for a long time. Now, thanks to
       the computer, they‟re becoming even more effective - especially at spotting lung cancer
       in its very early stage.

 This is an X-Ray of a human chest with evidence of a cancer. It‟s very difficult to spot. If it
could have been detected earlier when it was smaller, it would have been much easier to treat
successfully.

Bill Lampeter working under the direction of Dr. Dana Ballard at the University of Rochester is,
in effect, training a computer to spot those early, very small cancers. He programmed the
computer to examine 640 thousand individual points on the X-ray image.

Very small cancers, called nodules, appear as circles on X-rays. A computer was programmed to
identify circles in the image.

But not every round image is a nodule. Sometimes ribs appear as circle. The computer was
instructed to identify and ignore them.

Blood vessels, too, can show up as circular objects, so the computer was          programmed to
recognize and eliminate them.

With more processing of the image, to the computer presents a final display of all the circular
areas that could be cancer nodules. The doctor can now examine these areas in detail.

Soon lung cancer may be treated much earlier because the beginning stage, the nodule, can be
spotted by a computer programmed to read X-rays.

Text 16
                                         How is waste recycled?

When you recycle materials, you are helping conservation in three ways. You are helping to keep
down damage caused to the environment by cutting down trees or by mining for raw materials.
You are helping to save energy. You are also helping to cut down the problems of waste
disposal.

Paper

Most paper is made from wood pulp, which comes from trees. Whole forests have to be cut
down to provide us with newspapers. That is bad enough, but large amounts of energy are used
to turn the wood pulp into paper and to bleach it to make the paper white. This process releases
chemicals into our rivers and so causes water pollution.

Recycled paper must first have the link taken out. It is then turned into pulp and pressed back
into sheets of paper. Recycled paper is as good as new paper, although it is a little rougher and
not as white. Only about one-quarter of the world‟s paper is recycled. At least another quarter
could be saved.

Glass

Huge amounts of energy are used in making glass, because very high temperatures are needed to
melt down all the ingredients. If bottles and jars are thrown away when they are empty, all that
energy is lost. But new bottles and jars can be made out of a mixture of new glass and old,
broken glass, which is called cullet. This saves up to one-quarter of the energy needed to make
new glass.

Metals

Metal cans are made of aluminum, or steel coated with tin, or a mixture of these metals.
Aluminum cans are the most valuable to recycle. In the United States, over half of all aluminum
cans are recycled. Aluminum is made from an ore called bauxite, which has to be electrically
heated to a high temperature. Recycling saves 95 per cent of the energy needed to make new
aluminum cans.

Text 17

                                             Work and energy

Do you know that you are working when you are playing? To a scientist, work is any kind of
action that uses energy.

Energy is needed to do all types of work – for example, to throw a ball into the air and to catch it.
Energy is needed because something does not move unless you push or pull it. And it doesn‟t
stop moving unless you push or pull it. And it doesn‟t stop moving unless something else slows
it down. When you catch a ball, your hand can feel the ball pushing to continue moving. Inertia
is a basic characteristic of an object as it continues to stay at rest or continues to move.

If you want to start moving something or stop it from moving, you need to push or pull it. These
pushes and pulls are called forces. Forces are needed to overcome inertia. Forces are produced
by applying energy. The more force applied, the more energy used and the more work done.

When you lift a heavy box, potential energy changes to kinetic energy in your muscles. You use
more energy and do more work when you move a heavy box than when you lift a lighter box for
the same distance. You do more work when you lift a box up to a high shelf than when you lift
it onto a low shelf. If you carry a pile of books weighing 22 pounds (10 kilograms) up a flight of
stairs, you do twice as much work than if you carried an 11 pound (5 kilogram) pile up the same
flight of stairs. Since work is equal to force times distance, the energy you use is equal to the
weight of the books times the distance you moved.

Text 18



                                               Supplying energy

Humans need energy every day and night of the year in order to survive. Factories use energy to
make their machines work. We need energy in our homes for cooling, heating, lighting, and
cooking. Energy is needed to light up city streets at night. All types of transport rely on energy in
one form or another.

We can obtain this energy from two sources. We can use nonrenewable energy sources, such as
oil and coal, and convert the chemical energy from these sources into kinetic or electrical energy.
Or we can use renewable energy sources such as the sun, the wind, and flowing water.

A problem with some types of energy is that the energy is not always in the right place at the
right time, and sometimes it is not there in sufficient quantity. On a cold, dark day, we turn on
the heating to keep us warm and the lighting to help us see. On such days, power stations fueled
by nonrenewable energy sources usually supply as much electricity as we need. There is
normally no problem with energy supplies. But the same may not be true of renewable energy
sources. Solar power works best when the sun is shining. On a cold, dark day, there may not be
enough energy stored in solar cells to give us sufficient warmth and light. In a storm, there may
be more wind energy than we can use. But when the weather is calm, there may not be enough
wind to produce any energy.

All sources of energy put together is energy locked up in nuclei of atoms of matter itself. It is
called nuclear energy.
 There are great possibilities of using nuclear energy for world. A number of countries are
working at the development and construction of various kinds of locomotive, airplanes and other
means of transport. Many atomic powered ships have been already built. Nuclear energy is and
will be used in medicine, and in many spheres of life where the atom may find useful
application.

Text 19

                                              Vitamin

The vitamins necessary for a health body are normally supplied by a good mixed diet, including
a variety of fruit and green vegetables. It is only when people try to live on a very restricted diet,
or when trying to lose weight, that it is necessary to make special provision to supply the missing
vitamins.

 An example of the dangers of a restricted diet may be seen in the disease known as “beri-beri”,
which large numbers of Eastern people who lived mainly on rice used to suffer from. In the early
years of this century, a Dutch scientist called Eijkman was trying to discover the cause of beri-
beri. At first he thought it was caused by a germ. He was working in a Japanese hospital, where
the patients were fed on rice which had the outer husk removed from the grain. It was thought
this would be easier for weak, sick people to digest.

Eijkman thought his germ theory was confirmed when he noticed the chicken in the hospital
yard, which were fed on scraps from the patients‟ plates, were also showing signs of the disease.
He then tied to isolate the germ which he thought was causing the disease, but his experiments
was interrupted by a hospital official, who gave out the order that the huskless, milled rice, even
though left over by the patients was too good for chickens, and that it should be recooked and
the chickens fed on cheap , coarse rice with the outer covering still on the grain.

Eijkman noticed that the chickens began to recover on the new diet. He began to consider the
possibility that eating unmilled rice somehow prevented or cured beri-beri – even that a lack of
some ingredient in the husk might be cause the disease. Indeed this was the case. The element
needed to prevent beri-beri was shortly afterwards isolated from rice husk sand is now known as
vitamin B. the milled rice, thought more expensive, was in fact helping continuing the disease
the hospital was trying to cure.

Text 20

                                                Acupuncture

If you have ever had an operation, you were first put to sleep with a gas you breathed or by a
chemical injected into your body. Medical workers in the United States of America and Europe
have used these methods in operations since 1842. They have been valuable in preventing great
pain which would have occurred if the patient had not been put to sleep.
The Chinese, however, have been able to perform operations for about 4000 years without
putting the patient to sleep. They use a method called acupuncture. This involves sticking
flexible needles into certain parts of the body.

The person who performs the acupuncture must know how to insert the needles so the needles
themselves are not painful. This person also knows where to place the needles so the patients
feels no pain in the area where the operation is to be performed. The needles are not necessarily
inserted near the region where the pain is to be prevented.

Today, Chinese are learning to be more efficient and skilled in their use of acupuncture: but
more research should be done before the Chinese can explain more convincingly how it works.

A surgical patient is given a choice between having acupuncture or having one of the chemicals
used for putting him to sleep. It has been estimated that over half of the patients chose
acupuncture because there is no sickness after the operation, whereas the chemicals may make
the patient sick for a few hours or a day.

If the person has chosen acupuncture, the needles are inserted in the proper places. After several
minutes, the patient is examined to see if he or she can feel pain in the region where the
operation will be performed. If no pain is felt, the operation is performed. The patient is fully
awake and can feel the surgeon working.

Some doctors in the United States have been skeptical about acupuncture. However it is already
being used to a very limited extent in this country. It will be interesting to see if the method
becomes adopted here.

Text 21

                                            Silver, the Magic Metal

Most of us like silver. We search clouds for silver linings, lend an ear to silver-tongued speakers
and find silver hair splendid. Some ancient people called silver “white gold”. The two metals
were used in the earliest coins. They are neighbors in the periodic table of elements. Only silver
can match gold‟s ability to bend and stretch. You can draw one grain of silver into 400 feet of
wire, or beat it into leaf nearly 150 times thinner than this page. And, like gold, silver is
permanent wealth in the hand.

Silver has still more advantages. Nothing else reflects light so well and uniformly. Even the
thinnest sheet will reflect 95 percent of the light cast on it. Silver concentrates sun rays on solar
collectors, backs the best mirrors and protects the heat-reflecting gold films on office windows.
Silver will enable oxygen to kill bacteria. Hospitals clean their drinking water with silver carbon
materials.
No metal- not even copper- conducts heat and electricity so efficiently as silver. Silver-oxide
batteries power hearing aids, submarines and satellites. Small round plates of silver switch
current from wire to wire in car lights, telephones and computers.

Silver is also used to produce rainfall as well as photographs. Silver goes into use so rapidly that
for many years mines have not met world demand, estimated at more than 11000 tons 1981 two-
thirds of this amount came out of the earth. We made up the difference by recycling old coins,
computer wiring panels, used photographic materials and other silver scrap. Happily we can
reuse our old silver almost endlessly because little metal is lost at each transformation.

Text 22

                                              Science

       Science (from the Latin scientia, meaning "knowledge") is an enterprise that builds and
organizes knowledge in the form of testable explanations and predictions about the natural
world. An older meaning still in use today is that of Aristotle, for whom scientific knowledge
was a body of reliable knowledge that can be logically and convincingly explained.

       Since classical antiquity science as a type of knowledge was closely linked to philosophy,
the way of life dedicated to discovering such knowledge. And into early modern times the two
words, "science" and "philosophy", were sometimes used interchangeably in the English
language. By the 17th century, "natural philosophy" (which is today called "natural science")
could be considered separately from "philosophy" in general. But "science" continued to also be
used in a broad sense denoting reliable knowledge about a topic, in the same way it is still used
in modern terms such as library science or political science.

        The more narrow sense of "science" which is common today, developed as a part of
science became a distinct enterprise of defining "laws of nature", based on early examples such
as Kepler's laws, Galileo's laws, and Newton's laws of motion. In this period it became more
common to refer to natural philosophy as "natural science". Over the course of the 19th century,
the word "science" became increasingly strongly associated with the disciplined study of the
natural world, for example physics and chemistry. Many of the other areas of scientific study
outside the natural sciences have sometimes been classified as social sciences.

Text 23

                                         The solar system

        Our solar system consists of an average star we call the Sun, the planets Mercury, Venus,
Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. It includes: the satellites of the planets;
numerous comets, asteroids, and meteoroids; and the interplanetary medium. The Sun is the
richest source of electromagnetic energy (mostly in the form of heat and light) in the solar
system. The Sun's nearest known stellar neighbor is a red dwarf star called Proxima Centauri, at
a distance of 4.3 light years away. The whole solar system, together with the local stars visible
on a clear night, orbits the center of our home galaxy, a spiral disk of 200 billion stars we call the
Milky Way. The Milky Way has two small galaxies orbiting it nearby, which are visible from the
southern hemisphere. They are called the Large Magellanic Cloud and the Small Magellanic
Cloud. The nearest large galaxy is the Andromeda Galaxy. It is a spiral galaxy like the Milky
Way but is 4 times as massive and is 2 million light years away. Our galaxy, one of billions of
galaxies known, is traveling through intergalactic space.

        The planets, most of the satellites of the planets and the asteroids revolve around the Sun
in the same direction, in nearly circular orbits. When looking down from above the Sun's north
pole, the planets orbit in a counter-clockwise direction. The planets orbit the Sun in or near the
same plane, called the ecliptic. Pluto is a special case in that its orbit is the most highly inclined
(18 degrees) and the most highly elliptical of all the planets. Because of this, for part of its orbit,
Pluto is closer to the Sun than is Neptune. The axis of rotation for most of the planets is nearly
perpendicular to the ecliptic. The exceptions are Uranus and Pluto, which are tipped on their
sides.



Text 24

                                               Water

       Water is a chemical substance with the chemical formula H2O. Its molecule contains one
oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient
conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state, water vapor
or steam.

        Water covers 70.9% of the Earth's surface, and is vital for all known forms of life. On
Earth, it is found mostly in oceans and other large water bodies, with 1.6% of water below
ground in aquifers and 0.001% in the air as vapor, clouds (formed of solid and liquid water
particles suspended in air), and precipitation. Oceans hold 97% of surface water, glaciers and
polar ice caps 2.4%, and other land surface water such as rivers, lakes and ponds 0.6%. A very
small amount of the Earth's water is contained within biological bodies and manufactured
products.

        Water on Earth moves continually through a cycle of evaporation or transpiration
(evapotranspiration), precipitation, and runoff, usually reaching the sea. Over land, evaporation
and transpiration contribute to the precipitation over land.

       Clean drinking water is essential to human and other lifeforms. Access to safe drinking
water has improved steadily and substantially over the last decades in almost every part of the
world.

       There is a clear correlation between access to safe water and GDP per capita. However,
some observers have estimated that by 2025 more than half of the world population will be
facing water-based vulnerability. A recent report (November 2009) suggests that by 2030, in
some developing regions of the world, water demand will exceed supply by 50%.
      Water plays an important role in the world economy, as it functions as a solvent for a
wide variety of chemical substances and facilitates industrial cooling and transportation.
Approximately 70% of freshwater is consumed by agriculture.

Text 25

                                            Gemstone

         A gemstone or gem (also called a precious or semi-precious stone, or jewel) is a piece of
mineral, which, in cut and polished form, is used to make jewelry or other adornments. However
certain rocks, (such as lapis lazuli) and organic materials (such as amber or jet) are not minerals,
but are still used for jewelry, and are therefore often considered to be gemstones as well. Most
gemstones are hard, but some soft minerals are used in jewelry because of their lustre or other
physical properties that have aesthetic value. Rarity is another characteristic that lends value to a
gemstone. Apart from jewelry, from earliest antiquity until the 19th century engraved gems and
hardstone carvings such as cups were major luxury art forms; the carvings of Carl Fabergé were
the last significant works in this tradition.

        In modern times gemstones are identified by gemologists, who describe gems and their
characteristics using technical terminology specific to the field of gemology. The first
characteristic a gemologist uses to identify a gemstone is its chemical composition. For example,
diamonds are made of carbon (C) and rubies of aluminium oxide (Al2O3). Next, many gems are
crystals which are classified by their crystal system such as cubic or trigonal or monoclinic.
Another term used is habit, the form the gem is usually found in. For example diamonds, which
have a cubic crystal system, are often found as octahedrons.

        Gemstones are classified into different groups, species, and varieties. For example, ruby
is the red variety of the species corundum, while any other color of corundum is considered
sapphire. Emerald (green), aquamarine (blue), red beryl (red), goshenite (colorless), heliodor
(yellow), and morganite (pink) are all varieties of the mineral species beryl.

       Gems are characterized in terms of refractive index, dispersion, specific gravity,
hardness, cleavage, fracture, and luster. They may exhibit pleochroism or double refraction.
They may have luminescence and a distinctive absorption spectrum.

        Material or flaws within a stone may be present as inclusions.Gemstones may also be
classified in terms of their "water". This is a recognized grading of the gem's luster and/or
transparency and/or "brilliance". Very transparent gems are considered "first water", while
"second" or "third water" gems are those of a lesser transparency.



Text 26

                                             Engineer
        Engineers apply the principles of science and mathematics to develop economical
solutions to technical problems. Their work is the link between scientific discoveries and the
commercial applications that meet societal and consumer needs.

        Many engineers develop new products. During the process, they consider several factors.
For example, in developing an industrial robot, engineers specify the functional requirements
precisely; design and test the robot's components; integrate the components to produce the final
design; and evaluate the design's overall effectiveness, cost, reliability, and safety. This process
applies to the development of many different products, such as chemicals, computers,
powerplants, helicopters, and toys.

        In addition to their involvement in design and development, many engineers work in
testing, production, or maintenance. These engineers supervise production in factories, determine
the causes of a component‟s failure, and test manufactured products to maintain quality. They
also estimate the time and cost required to complete projects. Supervisory engineers are
responsible for major components or entire projects. Engineers use computers extensively to
produce and analyze designs; to simulate and test how a machine, structure, or system operates;
to generate specifications for parts; to monitor the quality of products; and to control the
efficiency of processes. Nanotechnology, which involves the creation of high-performance
materials and components by integrating atoms and molecules, also is introducing entirely new
principles to the design process.

        Most engineers specialize. Following are details on the 17 engineering specialties
covered in the Federal Government's Standard Occupational Classification (SOC) system.
Numerous other specialties are recognized by professional societies, and each of the major
branches of engineering has numerous subdivisions. Civil engineering, for example, includes
structural and transportation engineering, and materials engineering includes ceramic,
metallurgical, and polymer engineering. Engineers also may specialize in one industry, such as
motor vehicles, or in one type of technology, such as turbines or semiconductor materials.



Text 27

                                 Why do Earthquakes Happen?

        The danger from earthquakes is really real-they are probably the most terrible natural
disaster on earth. People used to think that earthquakes were punishment from an angry god. It is
only recently that scientists have begun to understand why earthquakes happen.

        Scientists could not understand earthquakes until they understood more about the earth‟s
surface. The science called plate tectonics provides an explanation. According to this science,
there twelve huge plates that make up the outer surface of the earth. The oceans and land rest on
these plates. The tectonics are the structure of the plates, which fit together like huge pieces of a
jigsaw puzzle.
        The plates do not fit perfectly, however –they are always moving. Some plates are slowly
moving apart and others are moving together. The plates that begin in the middle of the Atlantic
ocean are moving apart and the plates that meet in the Pacific Ocean are pushing together. In
fact, the Atlantic ocean is slowly growing larger and the Pacific ocean is getting smaller.
Earthquakes occur when two plates that are pushing against each other slide violently past each
other. A large amount of energy is released, and the land on top of the plates shakes, causing
cracks to appear in the ground and waves to form in the ocean. Terrible destruction can occur:
buildings can be destroyed, and fires can begin.

        Because most earthquakes occur at places where two plates push against each other, these
places, called faults, are very dangerous. The famous San Andreas Fault is the meeting of the
Pacific and the North American Plates. The San Francisco earthquake of 1906, which almost
completely destroyed the city, occurred because San Francisco is very close to the San Andreas
Fault.

       There is a “Ring of Fire” that surrounds the Pacific Ocean. About 30% of all earthquakes
occur in this zone. In February 1976 the worst earthquake in modern times stuck Guatemala city
in Central America. The earthquake occurred at the place where the North American Plate and
the Caribbean Plate push against each other, killing 20,000 people and leaving 1 million
homeless.

Text 28

                                  The discovery of the X-ray



         Scientists working on a problem do not know and sometimes can‟t even guess what the
final result will be. Late on Friday, 8 November, 1895, Professor Rontgen, German physicist,
was doing an experiment in his laboratory when he noticed something extraordinary. He had
covered an electric bulb with black cardboard, and when he switched on the current he saw little
dancing lights on his table. Now the bulb was completely covered; how then could any ray
penetrate? On the table there were some pieces of paper which had been covered with metal
salts. It was on this paper that the lights were shining. Professor Rontgen took a piece of this
paper and held it at a distance from the lamp. Between it and the lamp he placed a variety of
objects, a book, a pack of cards, a piece of wood and a door key. The ray penetrated every one of
them expect the key. He called his wife into the laboratory and asked her to hold her hand
between the lamp and a photographic plate.

       She was very surprised by this request, but she held up her hand for a quarter of an hour,
and when the plate was developed there was a picture of the bones of her hand and of the ring on
one finger. The mysterious ray could pass through the flesh and not through the bone or the ring.
       At a scientific meeting, Professor Rontgen called this new ray “the unknown”, the X-ray.
Doctors quickly saw how this could be used, and soon there were X-ray machines in all the big
hospitals. The most obvious use for this discovery was to enable doctors to see exactly how a
bone was fractured. Other uses came later. It was found that these rays could be used to destroy
cancer cells, just as they destroyed the healthy cells of the doctors who first used the machines.
Methods were found later by which ulcers in the stomach could be located, and the lungs could
be X- rayed to show if there was any tuberculosis present.

Text 29

                                       Scientific knowledge



        For me, scientific knowledge is divided into mathematical sciences, natural sciences or
sciences dealing with the natural world (physical and biological sciences), and sciences dealing
with mankind (psychology, sociology, all the science of cultural achievements, and every kind of
historical knowledge). Apart from these sciences is philosophy, about which we will talk later. In
the first place, all this is pure or theoretical knowledge, sought only for the purpose of
understanding, in order to fulfill the need to understand what is intrinsic and consubstantial to
man. What distinguishes man from animal is that he knows and needs to know. If man did not
know that the word existed, and that the world was of a certain kinds, that he was in the world
and that he himself was of a certain kind, he wouldn‟t be a man. The technical aspects or
application of knowledge are equally necessary for man and are of the greatest importance,
because they also contribute to defining him as man permit him to pursue a life increasingly
more truly human.

        But even while enjoying the results of technical progress, he must defend the primacy
and autonomy pure knowledge. Knowledge sought directly for its practical application will have
immediate and foreseeable success, but not the kind of important result whose revolutionary
scope is in large part unforeseen, expect by the imagination of the Utopians. Let me recall a well-
known example. If the Greek mathematicians had not applied themselves to investigation of
conic sections zealously and without the least suspicion that it might someday be useful, it would
have been possible centuries later to navigate far from shore. The first men to study the nature of
electricity could not imagine that their experiments, carried on because mere intellectual
curiosity, would eventually lead to modern electrical technology, without which we can scarcely
conceive of contemporary life. Pure knowledge is valuable for its own sake, because the human
spirit cannot resign itself to ignorance. But, in addition, it is the foundation for practical result
that would not have been reached if this knowledge had not been sought disinterestedly.

Text 30

                                      Can computer think?
        Can computer think? That depends on what by “think”. If solving a mathematical
problem is “thinking‟, then a computer can “think”. Of course, most mathematical problems can
be solved quite mechanically by repeating certain straightforward processes. Even the simple
computers of today can be geared for that. It is frequently said that computers solve the problems
only because they are “programmed” to do so. They an only do what men have them do. One
must remember that human beings also can only do what they are “programmed” to do so. Our
genes “program” us the instant the fertilized ovum is formed, and our potentialities are limited by
that “program”.

        Our “program” is so much more enormously complex, though, that we might like to
define “thinking” in terms of the creativity that goes into writing a great play or composing a
great symphony or conceiving a brilliant scientific theory. In that case, computers certainly can‟t
think and neither can most humans.

       Surely, if a computer can be made as complex as a human brain, it could be the
equivalent of a human brain and do whatever a human brain can do.

        To suppose anything else is to suppose that there is more to the human brain than the
matter that composes it. The brain is made up of cells in a certain arrangement and the cells are
made up of atoms and molecules in certain arrangements. If anything else is there, no signs of it
have ever been detected. To duplicate the material complexity of the brain is therefore to
duplicate everything about it.

       But how long will it take to build a computer complex enough to duplicate the human
brain? Perhaps not as long as some think. We approach a computer as complex as our brain and
we will perhaps build a computer that is at least complex enough to design another computer
more complex than itself. This more complex computer could design one still more complex and
so on.

       In other words, once we pass a certain critical point, the computer take over and there is a
“complexity explosion”. In a very short time thereafter, computers may exist that not only
duplicate the human brain-but far surpass it.

				
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