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the German mineralogist Friedrich Mohs. Here‘s the scale, from softest to hardest:

talc – easily scratched by the fingernail; gypsum – just scratched by the fingernail;

calcite – scratches and is scratched by a copper coin;

fluorite – not scratched by a copper coin and does not scratch glass; apatite – just scratches glass and is easily scratched by a knife; orthoclase – easily scratches glass and is just scratched by a file;

quartz – (amethyst, citrine, tiger‘s-eye, aventurine) not scratched by a file; topaz – scratched only by corundum and diamond;

corundum – (sapphires and rubies) scratched only by a diamond; diamond – scratched only by another diamond.

Even though diamond is only one level higher on the scale than corundum, diamond can be anywhere from 10 to hundreds of times harder than this class of gems.

It is the molecular structure of diamonds that makes them so hard. Diamonds are made of carbon atoms linked together in a lattice structure. Each carbon atom shares electrons with four other carbon atoms, forming a tetrahedral unit. This tetrahedral bonding of five carbon atoms forms an incredibly strong molecule. Graphite, another form of carbon, isn‘t as strong as diamond because the carbon atoms in graphite link together in rings, where each atom is only linked to one other atom.

Speech patterns

І. Decide which of these statements are true and which are false.

1. Diamonds are a form of sodium. 2. Diamond is the hardest mineral we know. 3. Friedrich Mohs was an Italian Physicist. 4. Quartz is harder than gypsum. 5. In diamonds, carbon atoms make a hexahedron unit.

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ІІ. Answer the following questions.

1. What physical phenomena influence the creation of diamonds? 2. What property is the criterion for ordering minerals in the Mohs Scale? 3. How many minerals are there in the Mohs Scale? 4. What makes diamond molecules so strong?

Text 11. Are Cell-phones Harmful?

Active Vocabulary:

All cell phones emit some amount of electromagnetic radiation. Given the close proximity of the phone to the head, it is possible for the radiation to cause some sort of harm to the 118 million cell-phone users in the United States. What is being debated in the scientific and political arenas is just how much radiation is considered unsafe, and if there are any potential long-term effects of cell-phone radiation exposure.

There are two types of electromagnetic radiation:

Ionizing radiation. This type of radiation contains enough electromagnetic energy to strip atoms and molecules from the tissue and alter chemical reactions in the body. Gamma rays and X-rays are two forms of ionizing radiation. We know they cause damage, which is why we wear a lead vest when X- rays are taken of our bodies.

Non-ionizing radiation. Non-ionizing radiation is typically safe. It causes some heating effect, but usually not enough to cause any type of long-term damage to tissue. Radio-frequency energy, visible light and microwave radiation are considered non-ionizing.

On its Web site, the FDA states that ―the available scientific evidence does not demonstrate any adverse health effects associated with the use of mobile phones.‖ However, that doesn‘t mean that the potential for harm doesn‘t exist. Radiation can damage human tissue if it is exposed to high levels of RF radia-

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tion, according to the FCC. RF radiation has the ability to heat human tissue, much like the way microwave ovens heat food. Damage to tissue can be caused by exposure to RF radiation because the body is not equipped to dissipate excessive amounts of heat. The eyes are particularly vulnerable due to the lack of blood flow in that area.

The added concern with non-ionizing radiation, the type of radiation associated with cell phones, is that it could have long-term effects. Although it may not immediately cause damage to tissue, scientists are still unsure about whether prolonged exposure could create problems. This is an especially sensitive issue today, because more people are using cell phones than ever before. In 1994, there were 16 million cell-phone users in the United States alone. As of July 17, 2001, there were more than 118 million.

Here are a few illnesses and ailments that have potential links to cell-phone radiation: cancer, brain tumors, Alzheimer‘s, Parkinson‘s, fatigue, headaches.

If you are worried about the potential hazards of cell-phone radiation, here are a few ways to reduce your risk:

Use a hands-free headset.

Use a phone that places the antenna as far away from you as possible.

Extend the antenna during use.

Limit calls inside buildings.

Limit use by children.

Speech Patterns

І. Decide which of these statements are true and which are false.

1. Cell phones emit big amount of electromagnetic radiation. 2. Radio-frequency radiation has the ability to destroy human tissue. 3. Scientists still discuss the possible harm of cell phones effect. 4. Children may use cell phones without any restriction.

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ІІ. Answer the following questions.

1. How many cell phone users were there in the USA in 2001? 2. What illnesses may be caused by excessive use of cell phones? 3. What are the forms of ionizing radiation? 4. What organ is particularly vulnerable to the effect of heat?

Text 12. The Internet

Active Vocabulary:

The Internet is a global system of interconnected computer networks linked by a broad range of electronic and optical networking technologies. The Internet carries a lot of information resources and services, especially the inter-linked hypertext documents of the World Wide Web (WWW) and the infrastructure to support electronic mail.

Most traditional communications media, such as telephone and television services, are reshaped using the technologies of the Internet, giving rise to services such as Voice over Internet Protocol (VoIP) and IPTV. Newspaper publishing has been reshaped into Web sites, blogging, and web feeds. The Internet has enabled the creation of new forms of human communications through instant messaging, Internet forums, and social networking sites.

The Internet was created in the 1960s when the USA funded research projects of its military agencies decided to build forceful computer networks. Now the Internet has no centralized governance in either technological realization or policies for access and usage.

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The terms Internet and World Wide Web are often used in everyday speech without much difference. However, the Internet and the World Wide Web are not one and the same. The Internet is a global data communications system. It is a hardware and software infrastructure that provides connectivity between computers. In contrast, the Web is one of the services communicated via the Internet. It is a collection of interconnected documents and other resources, linked by hyperlinks and URLs.

Speech Patterns

І. Decide which of these statements are true and which are false.

1. The Internet is a global system of computer networks connected by a wide range of electronic and optical networking technologies. 2. TV programs have been transformed into Web sites, blogging, and web feeds. 3. The Internet was created as forceful computer networks in the 1960s in the USA for military purposes. 4. The terms Internet and World Wide Web are one and the same.

ІІ. Answer the following questions.

1. What is the Internet? 2. What traditional communication media give rise to services such as Voice over Internet Protocol (VoIP) and IPTV? 3. What new forms of human communications were created in the Internet? 4. When was the Internet created?

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Text 13. DNA Stretching Mystery is Solved

Active Vocabulary:

Researchers in Europe have unravelled a mystery that has been puzzling scientists for years: what happens to a molecule of DNA when it is stretched to its breaking point.

Now Erwin Peterman and his colleagues appear to have answered the question. The researchers carried out a DNA-stretching experiment by attaching one end of each strand of a length of double-stranded DNA to a polystyrene bead. The beads could be pulled apart with a controlled and measurable force by lasers – a process called optical tweezing.

―Pulling the DNA from both ends is a bit like pulling on a jacket that has a double-ended zipper,‖ says Peterman. ―What we found was that at the transition force the zipper starts to come apart at either end, but remains zipped in the middle. In other words, the DNA comes apart at either end, and under tension this single-stranded DNA is 70 percent longer than double-stranded DNA.‖

It is a great work. It tells us about the way the structure of a single molecule is changing under tension, something we have not been able to see before. It looks as though they have solved the question, but as always it is very complicated. So this might not be the end of the story.

Speech Patterns

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І. Decide which of these statements are true and which are false.

1. The researchers have been stretching strands of DNA for ages. 2. The scientists have divided strands of DNA into two different parts. 3. A single-stranded DNA is as long as a double-stranded one. 4. The structure of a single molecule can be changed under pressure.

ІІ. Answer the following questions.

1. Who carried out a DNA-stretching experiment? 2. What was the DNAstretching experiment? 3. What happened to a molecule of DNA when it was stretched to its breaking point? 4. Is this experiment useful? Why?

Text 14. Status of Genetically Modified Products

Active Vocabulary:

The development of modern biotechnology is really a ground-breaking advance because of its enormous power to transform living things. New techniques such as tissue culture, cell culture and embryo transfer, as well as various techniques of molecular manipulation, have emerged. Transgenic technologies such as genetically modified organisms (GMOs) are now being widely used in crop breeding and commercial production.

There are a number of actual or potential benefits from GM crops. These include:

Enhanced crop yield and productivity;

More nutritious and higher quality products;

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Less need for pesticides and herbicides;

Greater efficiency in resource management;

Role as a bioreactor to produce raw materials for pharmaceuticals and other industries.

For critics, there are four main objections:

Consumers do not have enough information about GMOs.

There may be potential detrimental effects from eating GM foods, while there have not yet been objective studies to identify such effects, if they exist.

There may be unexpected environmental problems.

Using of GM crops may go against certain religious beliefs and tradi-

tions.

So, rapid introduction of GM products into the market is really amazing. Many of the key technologies are in the hands of the private sector, and dominated by a few companies. The use of transgenic modification could have benefits for developing countries only, due to an affordable cost.

So, there are some more problems of using these products.

Many developing countries can not afford the cost of biotechnology.

The crop genetic improvements that are currently available are not suitable for developing countries.

The question is who will assist developing countries, and what type of assistance is appropriate.

Population growth and food distribution will most likely remain the two most critical problems which mankind must face for many years to come. Biotechnology offers the potential to reduce uncertainty in the world‘s future food supply, in the face of a growing population and the limited carrying capacity of the Earth.

Speech Patterns

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І. Decide which of these statements are true and which are false.

1. Transgenic technologies have been known since ancient times. 2. Genetically modified food is very useful for our body. 3. GMOs may cause plenty of environmental problems. 4. A developing country should have a fortune of money to afford the cost of biotechnology.

ІІ. Answer the following questions.

1. What new techniques in modern biotechnology do you know? 2. What are pros and cons of GM crops? 3. What is the situation with GM products on the market? 4. How can you solve the problem of food supply for all the mankind?

Text 15. The Big Future of Nanotechnology

Active Vocabulary:

Nanotechnology deals in the realm of the nearly invisible. The word comes from the Greek nanos, meaning ―dwarf‖. But by most accounts, the technology‘s potential is anything but small. Scientists and engineers can now physical-

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ly work with materials at the atomic level to create stain-proof fabrics, scratchresistant paints and longer-lasting tennis balls. And researchers say new medical diagnostic tools and smaller, more efficient fuel cells and batteries based on nanoscience are on the way.

From computer chips invisible to the naked eye to microscopic machines that seek out and destroy cancers inside the human body, a lot of scientists argue that the potential of nanotechnology could be endless, but not without controversy.

―If we can get a nanoparticle into a cell, that might prove to be a new and useful drug delivery device,‖ says Ms. Kulinowski, Executive Director of the

Center for Biological and Environmental Nanotechnology at Rice University. ―On the other hand, it might prove to be a toxin to the cell either by punching a hole in the cell membrane or otherwise disrupting the cell‘s function‖.

Whether the benefits of nanotechnology outweigh the risks will determine the future of what many researchers hope will be the world‘s next industrial revolution.

Speech Patterns

І. Decide which of these statements are true and which are false.

1. Nanoparticles are very big. 2. Nanotechnology has a great potential. 3. There is no need to use nanotechnology in medicine. 4. Nanotechnology is a step to the industrial revolution.

ІІ. Answer the following questions.

1. What does the word nanos mean? 2. At what spheres of industry can you use nanotechnology? 3. Why is nanotechnology useful? 4. How do nanoparticles influence the cells?

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