Reader at Work - 2.pdf - reading - alisja

HALLEY'S COMET

A comet is an object that travels around the sun leaving a bright trail

behind. For more than two thousand years, the return of Halley's Comet has

been observed and recorded on Earth every 76 years. Its 1986 visit,

however, was the first time that humans took a close look at its nucleus. One

spacecraft went within a few hundred kilometres of the nucleus. Two Soviet

craft, Vega 1 and Vega 2, came within 10,000 km of the nucleus on March

6th and March 9th; and the European Space Agency's Giotto space probe

passed within 600 km of Halley's Comet on March 14th. Pioneer Venus

Orbiter found that the cloud of gases and dust which make up the tail spread

over a region about 20,000,000 km across, 15 times larger than the Sun.

Scientists also discovered that the comet was losing about ten metres of

material from its surface every orbit, suggesting a lifetime of about only

] ,000 orbits - in about 100,000 years it will disappear.

A. Mark the statements as True (T) or False (F).

1. Halley's Comet was first seen more than 2000 years ago.

2. In 1986, two of the spacecraft which observed Halley's Comet were from

the Soviet Union.

3. The sun measures 20,000,000 km across.

4. Halley's Comet has a lifetime of about 100,000 years left because it is

losing material from its surface every orbit.

1. How often can Halley's Comet be observed from Earth?

2. What is the tail of Halley's Comet made up of?

HIGH-RISE

Since the early days of civilised man, buildings have been getting

higher all the time. Today, all large cities have tall buildings, either for

use as offices or as flats. These are called high-rise buildings. The

tallest of a]i in fact, are not used for offices or for living, but are

special structures for radio and television. For instance,Warsaw Radio

Mast in Poland, which is 646 metres tall, is the tallest of such

structures. The world's tallest office building is the Sears Tower in

Chicago. This has 110 storeys, and reaches a height of 443 metres.

16,700 people work inside the building, and there are more than one

hundred lifts for their use.

But why do we have high buildings? Is there any real advantage?

The most common reason given is that in many cities there is a lack of

space.

The island of Manhattan, New York City, is a good example of

this . Here, office space is very expensive. There is no more land.

Buildings have to go up. The same reason is given for high office

buildings in Tokyo, London and other large cities of the world.

But what about people? Is it really necessary to build high

buildings for people to live in?

Today, there are many who believe high buildings actually damage

people's minds and feelings. These people believe high-rise buildings:

-have no advantages, except for their owners and for banks

-are not cheap to build

-do not help create open space

-destroy the landscape

-cause crime

-are not good for children

-are expensive to look after

High-rise buildings lower the quality of life. The following reports

show this.

Report from England, 1967: The higher people live off the ground,

the more likely they are to suffer from mental illnesses. Women,

because they spend most time at home, suffer most.

In October 1981, newspapers in the USA and the UK reported

plans for a 169-storey building in Chicago. If this is built, it will be

almost twice as tall as the 384-metre Empire State Building in New

York.

3. The report from Denmark .

a) shows more people live in high-rise buildings in Denmark than in other

countries

b) states the disadvantages of high-rise buildings for children

c) shows how women living in high-rise buildings suffer

d) says that crime rate is higher in high-rise buildings in Denmark than in other

countries

4. Which of the following is not true?

a) The tallest buildings in the world are special structures used as offices.

b) When people live in high-rise buildings, they are cut off from real life.

c) High-rise buildings are still built although they have many disadvantages.

d) Mental illnesses increase especially among women who live in high-rise

buildings.

ATOMS (1)

Atoms are the smallest particles of matter that have the properties

of the chemical elements - hydrogen, oxygen, iron, and so on. They

are so small that it is impossible to see them even with a high-powered

microscope. Everything on Earth is made up of atoms in different

5 chemical combinations. Water, for instance, is a compound of two

elements, two atoms of hydrogen and one atom of oxygen. However,

some elements, such as gold and diamonds exist uncombined.

Ninety-two elements occur naturally. They range from the lightest,

hydrogen, to the heaviest, uranium. Each of the elements has been

10 assigned a number - 1 for hydrogen, 8 for oxygen, 29 for copper, 92

for uranium. They are usually arranged on a chart called the periodic

table, which puts elements with the same chemical properties in the

same column. Thus, all inert gases, such as helium, appear in one

column in the periodic table.

The formulation of the atomic theory is one of the great

achievements of science. It has enabled us to understand the properties

of the elements , the basic building blocks of all matter, so that we

know which elements can combine with each other. The science of

chemistry is based on our understanding of atoms and their behaviour

in interacting with one another.

Another science called nuclear physics came into being to study the

structure of the atom itself. As scientists investigated the atom, it

became apparent that the atom was not a solid piece of matter, but was

made up of even smaller particles. The first subatomic particle that

25 scientists identified was the electron, a tiny piece of matter with a

negative electric charge. The weight of an electron was very small

indeed - approximately one eighteen-hundredth of the weight of a

hydrogen atom, the lightest of all the elements. Scientists came to

believe that the electrons orbited the nucleus of the atom, in which

30 almost all of the weight of the atom was concentrated. It is now

known that electrons revolve around the nucleus at incredibly fast

rates of speed.

For many years scientists did many different kinds of experiments

and all had the same idea about the structure of atoms. However, when

35 they managed to obtain more evidence, they had to modify the atomic

theory. There was not just one kind of particle in the nucleus of an

atom; there were two. One of these has a positive electric charge and

is called a proton. The other is neutral, that is, it has no electric charge.

For this reason, it was called a neutron.

A. Complete the following sentences.

1. Helium (line 13) is a(n)

2. Elements (line 17) are

3. An electron (line 25) is a(n)

4. If something is neutral (line 38), it

B. What do. the following refer to?

1. They' (line 8): Elements which

2. 'It' (line 16):

3. 'all' (line 34): all

4. 'these' (line 37): these

C. Mark the statements as True (T) or False (F).

1. The theory about the structure of atoms has changed through years.

2. An electron is heavier than a hydrogen atom.

3. Electrons turn around the nucleus at a low speed.

1. In what way are gold and diamonds different from other elements?

2. What does nuclear physics study?

E. Complete the following statement.

The periodic table arranges elements according to

Reader at Work - 2.pdf

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