Part II. The abc of Natural Science

Text 1. The Origin of Life.

Before you read the text check you understand the key words: universe, made from, energy, form, particle, atom, matter, molecule, living/non-living matter, cell, life.

The universe is energy. Energy comes in a variety of forms that include everything, from an atomic particle to a group of galaxies. Everything around us is matter and matter is made from atoms. We know over one hundred kinds of basic atoms. They correspond to basic elements like nitrogen, oxygen, carbon, and others. An atom is a unit of matter.

Atoms form groups called molecules. Different combinations of atoms or molecules created different kinds of matter. An oxygen molecule, for example, is made from two oxygen atoms. A carbon dioxide molecule is made from two oxygen atoms and one carbon atom.

There are two basic types of molecules: small molecules and macromolecules. Small molecules are in non-living matter -minerals, air, and water. Macromolecules are made from many small molecules. They exist in living matter, i.e. in plants and animals including people. Macromolecules also exist in some synthetics like polythene and nylon.

Macromolecules are not living matter but they combine to create cells. Cells are basic units of life. This combination of non-living matter to form living matter is called "the miracle of life".

Some living matters like bacteria are made from one cell. Plants and animals, on the other hand, are made from millions of cells. A cell can produce more cells. A human being comes from only one cell. A person is an intelligent form of energy. He or she observes the universe and thinks about the origin and meaning of life.

Exercise 1. Match the words from the text:

1. macro a. matter

2. living b. particles

3. atomic c. energy

4. basic d. elements

5. intelligent e. molecules

Exercise 2. Circle the correct form of the verbs in brackets:

1. Everything (is/are) matter.

2. Macromolecules (exists/exist) in polythene and nylon.

3. How (do/does) non-living matter form living matter?

4. (Is/Are) carbon atoms present in your body?

5. People (think/thinks) about the origin and meaning of life.

Exercise 3. Complete the sentences with the correct form of the verbs in brackets:

1. A cell _____ (result) from a combination of macromolecules.

2. An atom _____ (not/be) living matter.

3. Macromolecules _____ (not/be) present in the sun.

4. A plant _____ (have) millions of cells.

5. An atom _____ (not/have) life.

6. Carbon atoms _____ (not/form) oxygen.

Exercise 4. Fill in the gaps with these words study, and, studies, are, has, aren’t:

Science _____ the variety of forms. Some forms _____ intelligent and some _____ . Biologists _____ living matter. Biology _____ two basic branches of study: Botany _____ Zoology.

Text 2. The Cosmic Web.

Before you read the text check you understand the key words: density, expansion, contraction, space-time, linear time, birth, growth, nuclei, stardust, aspect, pull of gravity.

Cosmologists use linear time to explain the birth and growth of the universe. Our universe is probably between 12,000 and 15,000 million years old. It starts with a Big Bang and includes the following events and protection: at zero second, before time begins, everything is together at a point of infinite density. This causes an extreme temperature that produces an explosion - the Big Bang. The universe starts expanding and energy, forces, matter and space-time emerge. Then, the temperature goes down and the basic forms of matter appear and evolve. At 50,000 million years, the cosmos holds its expansion and starts a contraction. 1,000 million years later it collapses in a ball of fire similar to the Big Bang - a Big Crunch.

Right after the Big Bang, particles called quarks unite in groups of three to form the first nucleons: neutrons and protons. Other particles like neutrinos, positrons and electrons also appear. Time passes and the nuclei of hydrogen (deuterium), helium and licium take form. After that, the first atoms and molecules of hydrogen gas emerge.

The pull of gravity forms clouds of gases and these clouds become stars and galaxies. The stars bake the nuclei of helium, carbon, silicium and iron that form the stardust. This dust makes up the asteroids and planets.

Some cosmologists don't agree with this theory. They explain that the expansion of the universe is accelerating. Another theory says that the universe is in constant reproduction. This means that there are infinite "universes". There isn't one absolute theory, but an important observation is that the universe works in a rhythm of expansion and contraction.

The universe has only one basic component: energy. All the forms, from atoms to rocks, plants and people are different aspects of the same energy.

Exercise 1. Look for the words on the left in the text. Then, match them with the correct meaning. Example: 1-c.

1. density a. explosion

2. Big Bang b. evolution

3. Big Crunch c. compactness

4. growth d. harmonious movement

5. rhythm e. extreme contraction

6. unite f. appearance

7. aspect g. get together

Exercise 2. Complete the following questions with a / an / the. Put an “x” when no word is necessary:

1. What is _____ linear structure?

2. How does _____ universe begin?

3. Why do _____ cosmologists use a linear structure?

4. Where does _____ energy come from?

5. What is _____ atom?

6. What causes _____ expansion and a contraction?

7. What makes up _____ nucleus?

Exercise 3. Complete the following sentences with these words become, moves, makes up, unite, comes:

1. Quarks _____ to form nucleons.

2. The universe _____ in a rhythm of contraction and expansion.

3. The clouds of gases _____ stars and galaxies.

4. Stardust _____ the asteroids and planets.

5. Life _____ from stardust.

Exercise 4. Correct the form of the verbs when necessary:

1. People uses time to describe the past, present and future.

2. Gravity attracts objects to the centre of our galaxy.

3. The cosmos stop its contraction and begins its expansion.

4. There is a black hole at the centre of our galaxy.

5. The basic forms of matter appears and evolve when the temperature goes down.

Text 3. From Inert Matter to Intelligent Life.

Before you read the text check you understand the key words: solar system, cloud, nebula, rotate, space, contract, star, join, asteroid, meteorite, radiant/electric energy, atmosphere, dynamics.

Our solar system is 4,500 million years old. In a solar system, the sun and the planets form at the same time. They form from a cloud of gases called nebula. A nebula rotates in space and the force of gravity pulls material to its centre. The nebula contracts and its centre gets hot. This hot centre becomes a star.

The outer part of the nebula is not so hot. When the temperature goes down the gases condense into particles of dust. The dust slowly sticks together and forms the planets. Life on our planet begins from the dust of a dying star.

Chronology of Life on Earth

4,500 million years A.C.: the planet temperature is very high. There are many volcanoes but there is no biological life. Meteorites fall from outer space and volcanic eruptions prepare the Earth crust. Gases from the volcanoes form the initial atmosphere. The temperature goes down; oxygen and hydrogen join and form the first lakes and oceans. Scientists believe that life begins in these waters.

The first waters contain many kinds of small molecules that change their composition. Radiant energy from the sun and electric energy from lightning recombine the small molecules into complex molecules. These complex molecules contain carbon, an essential element for life. Time passes and the first macromolecules of DNA appear. These macromolecules self-reproduce and join others to make up cells, the basic units of life. This theory explains that there is potential for life in inert matter. In humans, inert elements produce the sperm and the ovule. The sperm and the ovule form a unicellular egg (one cell) and from this cell, around sixty billion cells come to life. The combination of inert parts to form a living whole shows the basic dynamics of life.

Exercise 1. Now read the article and put the following events in chronological order:

a. The first macromolecules of DNA appear.

b. The gases condense and form particles of dust.

c. The nebula contracts.

d. Gases from the volcanoes form the initial atmosphere.

e. Gravity pulls material to the centre of the nebula.

f. The dust forms the asteroids and the planets.

Exercise 2. Complete the following sentences using words from the text:

1. A star and a group of planets form a _____.

2. The _____ and the planets form at the same time.

3. A theory explains that there is potential for life in _____ matter.

4. A _____ egg is a combination of a sperm and an ovule.

5. Another way to say deoxyribonucleic acid is _____.

Exercise 3. Complete the following questions with When, What, How, Where:

1. _____ old is our solar system?

2. _____ do the planets come from?

3. _____ makes the nebula contract?

4. _____ do the gases condense and form particles of dust?

5. _____ do macromolecules do to make up cells?

Exercise 4. Fill in the gaps with there isn't, there aren't, is there, are there, there are, have, has:

1. _____ a macromolecule in the sun?

2. _____ any young nebula in outer space?

3. Gases from the volcanoes form the initial atmosphere but _____ an ozone layer.

4. _____ many different natural elements in the universe.

5. _____only a few cells in our body.

6. A cell _____ life.

7. DNA macromolecules _____ carbon atoms.

Text 4. Brain and Knowledge.

Before you read the text check you understand the key words: brain, left/right hemisphere, process, analysis, synthesis, reasoning, learning, senses, nerve cells, electrical/chemical impulse, knowledge, branches, philosophy, relay.

The American psychobiologist Roger Sperry shared a 1981 Nobel prize for his discoveries about the human brain. He studied the two brain hemispheres and presented laboratory proof of many interesting facts. According to him, the left hemisphere separates the information into parts and studies each part. This hemisphere also looks for the similarities among all the parts. This complete process is called analysis. Our left hemisphere is very curious and is always asking questions about everything. It dominates the right hemisphere.

The right hemisphere is different. It looks for unity and connects all the parts that the left hemisphere separates. This complete process is called synthesis. Analysis and synthesis determine reasoning and the learning process.

The separation and connection of information into parts and wholes show the basic dynamics of thought.

Our senses are windows to the world. The information enters through the senses and travels through nerve fibres. These long fibres of nerve cells are our body's electric circuits. When we read, for example, our sense of sight detects changes in the levels of light on the paper (black on white). These changes form the letters and the words. Our eyes perceive the changes and convert, them into electric signals that take turns with chemical signals to transmit the information. A nerve cell has three main parts: dendrites, nucleus and axon. The dendrites receive the information and send it through the axon. At the end of the axon the electric signals become chemical signals, cross to the next cell and continue the relay. There is a kind of intelligence in the cells. They organise and cooperate to perform a task. Intelligence gives us the ability to construct a mental model of the world, live in it, solve problems and accumulate knowledge.

As human knowledge increased we divided it and organised it into branches. Knowledge is one large subject that includes many divisions with a common objective: to understand our origin, reason for being and place in the universe.

Exercise 1. Read these sentences and choose the closest meaning to the underlined word:

1. The brain has two hemispheres: the left and the right.

a. specializations b. parts c. names

2. In the 70's, R. Sperry presented information to the brain and monitored its process.

a. what it looked like b. how it worked c. how it separated

3. Analysis and synthesis determine reasoning and the process of learning.

a. exploring b. observing c. understanding

4. The dendrites receive the information and send it via the axon.

a. photos b. data c. report

Exercise 2. Find the nouns of these verbs in the text:

Example: inform – information

1. analyse, 2. connect, 3. learn, 4. know.

Exercise 3. Fill in the blanks with the proper form of the words in brackets:

1. People use both _____ (analise) and _____ (synthesise) to solve problems.

2. It is easy to see the _____ (connect) between Philosophy and Science.

3. Man created the _____ (divide) of knowledge.

4. _____ (learn) is a lifetime process.

5. In the 70's R. Sperry _____ (study) how the two brain hemispheres work.

6. He _____ (present) data to the brain.

7. He _____ (observe) that the left hemisphere separated the information into parts.

8. He _____ (discover) that the right hemisphere connected the parts.

9. He _____ (receive) a Nobel Prize for his discoveries in 1981.

Exercise 4. Fill in the blanks with in, and, between:

1. Andreas Vesalius produced the first modern anatomy of the brain _____ 1543.

2. Franz Anton Mesmer pioneered the use of hypnosis _____ 1800 _____ 1815.

3. _____ 1861 Paul Broca detected the main speech area in the left hemisphere.

4. _____ 1969 _____ 1980 Sperry discovered hemisphericity.

Text 5. Composition of Matter.

Before you read the text check you understand the key words: mass, condensed, absorb, vibrate, temperature, heat, solid, liquid, gaseous, plasma, states, charged, bombarding.

Matter and Energy

1. Matter is anything that has mass and occupies space. It is found in three different states: solid, liquid and gaseous. Matter, as Albert Einstein explained in his Theory of Relativity, can also be described as a condensed form of energy. In Einstein's own words: "Mass and energy are two different aspects of the same thing".

We can see this in nuclear fission. The energy condenses to form a nucleus. When we bombard the nucleus with a neutron, the nucleus separates and releases some of the energy in the form of heat.

Atoms

2. An atom, a basic unit of matter is a packet of energy with electric charges. Except for hydrogen, which has no neutrons atoms are composed of a nucleus with neutrons and protons and a cloud with electrons orbiting the nucleus. The protons have a positive (+) charge. The electrons have a negative (-) charge. The neutrons have no charge. Opposite charges attract and like charges repel.

The Vibration of Matter

3. The energy contained in atoms and molecules makes them vibrate and this vibration produces heat. Matter expands with heat. In an iceberg (solid matter), for example, the molecules absorb radiant energy from the sun and vibrate even more. Their temperature increases, they expand and form water (liquid matter). The molecules in the water vibrate until they evaporate and go up in the air (gaseous matter). When the temperature decreases, their vibration slows down and they condense into drops that fall as rain. Water is a liquid composed of two gases: oxygen and hydrogen.

Plasma

4. In a gas atom like hydrogen, when the vibration increases the heat makes the atom expand more and lose its electron. The hydrogen atom becomes two separate charged particles: proton (+) and electron (-). Each of these particles is called plasma – a positive plasma and a negative plasma.

5. Plasma is not only produced by heat but also by particles bombarding the atoms. We can find plasma produced by heat in the sun, and plasma produced by particles bombarding the atoms in the ionosphere. We can also find artificial plasma during electric welding and inside flourescent lamps.

6. Interstellar space, the stars, and most of the universe is plasma. Our planet is a tiny mass vibrating in a sea of plasma.

Exercise 1. Read the list of topics (a-g) and match them with the paragraphs (1-6). There is one extra topic:

a. The stars are plasma.

b. Vibration produces changes in the states of matter.

c. Matter is a condensed form of energy.

d. Plasma can be natural or artificial.

e. A neutron is plasma.

f. The composition of an atom.

g. The vibration of energy.

Exercise 2. Match the verbs on the left with their meanings on the right:

1. go up a. make more concentrated

2. slow down b. move to the top

3. condense into c. caused by

4. produced by d. decrease the velocity

Exercise 3. Complete the following questions with the missing words:

1. Who _____ Albert Einstein?

2. When _____ he born?

3. What _____ he prove?

4. _____ you know that the Big Bang came from a positive plasma?

5. _____ there televisions before Einstein?

Exercise 4. Fill in the blanks using these linking words and expressions:

suddenly, when, but, and, one day, in the end, then

Albert Einstein was born in Germany in 1879.1 _____ he was a child, he was not a very good student 2 _____ he liked Physics very much. 3 _____, his father showed him a compass. The compass made him wonder about the connection between the needle 4 _____ the north pole. 5 _____, his interest in Physics increased even more. He moved to Switzerland to study and finished his studies in 1900. In 1913, he became director of Physics in an institute in Berlin. In 1916, he published his Theory of Relativity which 6 _____ made him famous all over the world. It was difficult for Albert to prove his theories but 7 _____ he succeeded. He received the Nobel prize for Physics in 1921. He died in Princeton in 1955.

Text 6. The Electric Charge.

Before you read the text check you understand the key words: electric charges, opposite types, duality, cloud, collide, top, bottom, lightning, thunder, conductor, insulator, store (v), flow, free (v-adj).

Opposite Charges and Interactions

Benjamin Franklin, inventor of the lightning rod, explained that positive (+) and negative (-) charges are opposite types of the same thing. Opposites are a basic characteristic of nature. They interact to show nature's duality: positive-negative, good-bad, (1)_____.

An interesting experiment to see the interaction between opposite electric charges is that of the plastic comb and the piece of paper. Rub a plastic comb on your hair. When you do this, your hair frees electrons. These free electrons flow from your hair to the comb and, as a result, there is an excess of electrons on the comb. Next, put the comb near a small piece of paper. The comb attracts the piece of paper because the electrons in the comb repel the excess electrons and the protons in the paper attract them. This happens because different charges attract and (2)_____.

Another example of interaction between electric charges is that of lightning. During an electric storm, water and ice particles collide inside cumulonimbus clouds. As a result, the positive charges move to the top of the clouds and the negative charges move to the bottom. The movement generates static electricity. When the negative charges flow back to (3)_____ they produce heat and emit light. Lightning is an electric discharge in the air. Thunder is a wave of pressure that occurs when the hot and violent lightning expands the cold air.

Electricity

The electric charge is also called electricity. We can generate electricity to illuminate our cities or we can store it in a battery to transport it. Electricity is a flow of electrons through a conductor. Copper is a good conductor so we use it in electric wires. PVC, on the other hand, is (4)_____ and we use it to cover copper wires.

A simple electric circuit includes a battery with chemical paste, a carbon rod, a wire and a light bulb. The chemical paste contains an excess of electrons so when you connect the two poles of the battery, the copper wire attracts electrons. The electrons in the chemical paste repel the electrons in the carbon rod and make them flow through the copper wire. When they arrive at the filament inside the bulb, they produce heat and emit light. That is why we say that (5)_____.

The nature of the electric charge is a mystery but we know that the interaction of the electric charges in space-time is responsible for the existence of nature.

Exercise 1.Match the phrases (a-e) with the gaps in the text (1-5):

a. the positive charges

b. a good insulator

c. something-nothing

d. like charges repel

e. light is a photoelectric effect

Exercise 2. a) The following words are adverbs. Look for their adjective form in the text:

Example: positively – positive

1. freely, 2. violently, 3. electrically, 4. chemically.

b) Complete these sentences with one of the words above:

1. _____ charged protons are made of quarks.

2. Atoms are _____ neutral.

3. In water, electrons flow _____.

4. Lightning is a _____ flash in the air.

5. We can store electricity _____.

Exercise 3. a) Read the following information about electricians' safety at work:

Electricians wear safety clothes like rubber shoes and gloves because accidents sometimes happen. Rubber is an insulator. Electrons can't go through it. Electricians usually turn off the electric power before working. They don't work outside when it is raining because water is a conductor. Electricians are not afraid of electricity but they respect its power.

b) Now use the note above to complete these sentences: When you work with electricity...

1. you can _____ accident.

2. you don't have to _____ but you have to be careful.

3. you have to _____ the electric power.

4. you can't _____ when it's raining.

Exercise 4. Fill in the blanks with have to, don't have to, can, can't:

During an electric storm...

1. you _____ work with metals in the open air.

2. you _____ look for a shelter.

3. you _____ be afraid, you have to be careful!

4. you _____ go out in a city.

Text 7. Duality.

Before you read the text check you understand the key words: energy, force, space, time, totality, cools off, decays, cycles, spontaneity, parts, wholes.

To understand duality we first need to understand totality. Everything is energy in its different forms and totality is the sum of all the forms. Each form has two parts that complement each other. Duality refers to these two parts. For example, energy needs a force to construct a form. Energy cannot work without a force and force cannot act without energy. Energy-force is a basic universal duality.

The new model of the atom shows how energy forms a duality. First, energy accumulates to form a neutron without a charge. The neutron cools off, decays into a proton and obtains a positive charge. Finally, the proton decays into an electron with a negative charge, and a neutrino with almost no charge. Positive - negative is a duality. They are two parts of the same energy that interact to construct forms. Stephen Hawking explains that, after a long time, some protons decay into little black holes and disappear. Energy follows a cycle: it goes from zero (neutron) to positive (proton) to negative (electron) and back to zero.

Duality is the basic characteristic of the nature that gives points of reference to locate and compare things in space-time. We can see duality in everyday life: man-woman, day-night, good - bad are all examples of duality. But, what is the origin of duality? Albert Einstein and a group of scientists discussed the origin of duality. They said that everything has a cause and an effect, and that this forms an infinite chain (cause-effect-cause…). They explained that there must be a single essence from where everything starts and follows a cycle. This one essence has no cause and they named it “the uncaused cause”. The uncaused cause is spontaneity. Energy spontaneously emerges from a vacuum and creates parts with individual identities to form wholes. Is the universe then an act of spontaneity?

There are four basic universal forces that interact for energy to construct forms in space. They are the strong and weak nuclear forces, electromagnetism and gravity. At present, scientists are trying to prove that these four forces are different aspects of only one force.

Exercise 1. Then read the following statements and tick the ones related to the reading:

1. Everything has two parts.

2. Energy needs force.

3. Positive and negative are two parts of the same energy.

4. Time is relative.

Exercise 2. Go back to the text and find the words needed to form dualities:

1. energy, 2. space, 3. part, 4. positive, 5. cause.

Exercise 3. Fill in the blanks with the proper form of the verbs in brackets:

1. Scientists _____ (try) to prove that there is only one universal force.

2. The basic forces _____ always _____ (interact) to construct forms.

3. Right now, millions of galaxies _____ (take) form.

4. At this moment, millions of neutrons _____ (pass) through your body.

5. What _____ you _____ (think) about?

Exercise 4. Fill in the blanks with and, also, but, too:

1. Energy and force work together to construct forms, _____ they need space to do that.

2. Science explains that space and time form a duality _____.

3. Neutrons decay into protons _____ protons decay into electrons and neutrinos.

4. Potential and kinetic energy are _____ a duality.

5. Duality is the origin of good _____ bad.

Text 8. Fields and Forces.

Before you read the text check you understand the key words: spinning, generates, magnetic field, currents, magnet, line up, behave, gravity, gravitational field, electromagnetism, shield.

We know that an atom is made from protons and neutrons in a nucleus, and electrons spinning around this nucleus. The protons have a positive electric charge and the electrons have a negative electric charge. The neutrons have no electric charge. As the electrons spin around the nucleus, they produce small currents. These currents create a magnetic field around the electrons and the atom. This magnetic field makes the atom behave like a small magnet.

Magnets can be natural or artificial. The Earth, for example, contains magnetic substances in its nucleus. These substances, which are also in our body, make our planet a big natural magnet. That’s why when you hang a bar magnet from a thread in a horizontal position, its north pole points to the geographic north pole of the Earth. A bar magnet is an artificial magnet. This type of magnets is usually made from a combination of elements that contain iron, cobalt or nickel.

Iron does not always behave like a magnet and this is because its atoms are usually disorganised. A needle, for example, that contains iron is not a magnet but when you rub the needle with a magnet, its atoms line up and the needle becomes a magnet. The needle can then attract other metals. This property of some substances to attract metals is called magnetism.

Electromagnetism and gravity are two basic forces of nature. They are very similar and scientists are trying to unify them. Electromagnetism works in small objects – it attracts the electrons from the atomic nucleus and maintains them in place. Gravity works with big objects – the pull of gravity from the nucleus of the Earth maintains our atmosphere in place. Both, the electrons and the Earth, spin and generate an electric and a magnetic field around them. These fields make up our planet’s electromagnetic shield.

All our senses work with electric impulses from and to the brain. These impulses create an electromagnetic field inside our body. Is there an electromagnetic shield around us?

Exercise 1. Look for words in the text derived from the nouns below. Identify if it’s a noun or an adjective:

Example: gravity – gravitational (adj.)

1. magnet, 2. atom, 3. geography, 4. electron, 5. sphere.

Exercise 2. Fill in the blanks with the proper form of the verbs in brackets:

1. We (know/are knowing) that the universe has two poles.

2. Right now we (stand/are standing) on the surface of the Earth.

3. At this moment our planet (spins/is spinning) around the sun

4. Cosmologists (believe/are believing) that gravity and electromagnetism are only one force.

5. Magnets (attract/are attracting) metals.

Exercise 3. Fill in the blanks with one, ones:

1. Some substances can attract metals. The _____ we use to make magnets are iron, nickel and cobalt.

2. A deuterium atom has a proton and a neutron. Which of these two nucleons is the _____ without a charge?

3. Which force is the _____ that holds the atmosphere in space?

4. Among scientists, physicists are the _____ who are trying to unify all the forces.

Exercise 4. Fill in the blanks with these words: someone, somewhere, anyone, anything, everywhere

1. In the future _____ will prove all the forces are really one.

2. _____ you go, you are within fields and forces.

3. Many scientists believe that _____ in our galaxy there are other planets with intelligent life.

4. Is there _____ smaller than an electron?

5. Does _____ in your class know about electromagnetism?

Text 9. Waves and Particles.

Before you read the text check you understand the key words: light, electromagnetic radiation, string, wave, particle, dual, quantum/photon, orbit, energy level, star, galaxy, collapse, black hole.

Light is electromagnetic radiation from atoms. It is made from small packets of energy. Each packet is called a quantum or photon. In atoms the electrons are always travelling around the nucleus in different orbits. Each orbit has a different energy level. When a photon (a particle of light) hits an atom, one of its electrons absorbs extra energy and moves to a higher energy level. When the electron returns to its original orbit, it emits a light photon and loses some energy. The colour of the light depends on how much energy the photons contain. In blue light, for example, the photons contain more energy than in red, yellow or white light.

For many years scientists studied light. Some believed that it moved in waves and other that it moved in currents of particles. Juan Maldacena, a physicist from Harvard University, received a UNESCO prize for his theory Black Holes in String Theory. He proved that light waves are caused by of small strings that roll in and contain black holes like galaxies do. These so-called micro galaxies emit photons and these photons form currents of particles near the waves. Maldacena’s theory finally explained the dual behaviour of light – light behaves like both waves and particles. His theory shows that a light particle and a galaxy have similar behaviour. This means that the force of gravity that forms the galaxies and the electromagnetism that holds the atoms and molecules together is probably the same force.

What is a Black Hole?

In a star there are two main forces: expansion and gravity. In a blue star, when the force of gravity is stronger than the force of expansion the star collapses at its centre. Then, the pull of gravity from the centre of the star is so strong that it even swallows the light! This makes the star invisible: a black hole. Around each black hole there is an area called event horizon which emits radiation. There is a black hole at the centre of our galaxy.

Exercise 1. Say if the statements are true or false:

1. Light is radiation.

2. A photon is a packet of energy.

3. Light moves both in waves and in particles.

4. There is a black hole at the centre of our galaxy.

Exercise 2. List the comparative form of these adjectives fast, small, hot, interesting.

Exercise 3. Use the comparative form of the adjectives in Ex.2 to complete these sentences:

Example: A particle of light (small) an electron.

A particle of light is smaller than an electron.

1. The waves in white light (long) the waves in red light.

2. Maldacena’s theory of light (interesting) Newton’s.

3. Nothing travels (fast) than light.

4. Blue light (hot) red light.

Exercise 4. Complete the paragraph with the comparative form of the adjectives below:

easy, famous, complete

Maldacena is an Argentine scientist. In the US, many scientists know him. He’s _____ there than in Argentina. He used other theories to make a new theory that is _____ than Newton’s and Einstein’s. Thanks to Maldacena, the structure of matter is _____ to understand now than a few years ago.

Text 10. Methods and Theories.

Before you read the text check you understand the key words: hypothesis, validity, strict, replace, sound, heat, sustainable, values, place (v), well-being, to obtain, to take into account, generation.

About 350 years ago, Galileo Galilei (1564-1642) changed scientists' attitudes towards Science. He developed the scientific method used to obtain theories that explain how nature works. This method, which is still in use today, includes the following steps:

♦ Identification of the problem.

♦ Formulation of a hypothesis based on collected and analysed data.

♦ Testing of the hypothesis to check its validity.

♦ Development of a theory.

Science is strict in its methodology but it welcomes change. In Science there has never been one absolute theory. We are constantly obtaining new information, making new observations and carrying out new experiments. As a result, new theories which replace or expand old ones are postulated and this is what leads to advances in Science.

There are two main types of theories: the theories of principles and the constructive theories. The theories of principles use analysis: we observe an event and explain it through the use of mathematics and experiments. Constructive theories, on the other hand, use synthesis. In these theories we use the information from the theories of principles to construct more complex theories. For example, the theory of principles proved that matter vibrates. Later, constructive theory used this information to prove that, sound, heat and radiation derive from vibration.

Especially in the last 200 years there has been great scientific progress. The application of scientific discoveries has helped develop technology and advance our knowledge of the world. Science has brought our countries together and we now have the possibility of sharing our knowledge and solving our problems. We are becoming a world community and this is science's most valuable contribution. However, as the World Commission on Environment and Development has stated, current trends in global development are not sustainable. Development should take into account the needs of both present and future generations. Scientific knowledge is important, but only the re-examination of our moral values will place Science on the right path to contribute towards the well-being of humanity.

Exercise 1. Read the article and mark the following statements right or wrong. Correct the wrong statements:

1. Science has no limit.

2. The scientific method has helped us obtain theories.

3. Science has found an absolute theory.

4. The constructive theories use the analytic method.

5. Development should consider both present and future generations.

Exercise 2. Match these verbs with their definition. Example: 1-c:

1. hypothesis

2. validity

3. theory

4. sustainable

5. method

a. a process that can continue for a long time.

b. a way of doing something.

c. an idea that tries to explain something about life or the world.

d. acceptability

e. an idea which has not yet been shown to be true.

Exercise 3. Use the present perfect form of the verbs in brackets:

1. In the last 100 years Science _____ (bring) changes in the way we live.

2. There _____ (be) many advances in communication technology.

3. We _____ (never lose) the hope for a better world.

4. The WCED _____ (state) that current development is not sustainable.

5. The scientific method _____ (help) us formulate theories for many years.

6. Science _____ (always welcome) new theories.

7. Maldacena _____ (just make) a new discovery.

8._____ (ever make) you a big change in your life?

Exercise 4. Work in groups:

Make a list of positive and negative things about technology.

Use the following to express your opinion.

Personally I think/1 believe / In my opinion /However / but,...

Ex: Personally, I think technology has helped us communicate.