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11. Study the text for more detailed information about lasers. The Past and the Future of the Laser

A laser is a source of light but unlike anything that had ever been seen before 1960 when Theodore H. Maiman of Hughes Aircraft placed a specially prepared synthetic ruby rod inside a powerful flash lamp similar to the type used for high-speed photography. Activating the flash lamp produced an intense pulse of red light, which possessed the unique properties of monochromicity (the light is of the same wavelength or colour), coherence (all the waves move precisely in step), and directionality (the beam can be easily manipulated). These features account for the enormous difference between the output of a laser and that of an incandescent light bulb.

With Maiman's invention the laser age was born. Everybody became interested in exploring this promising area of science. Within a very short time, numerous solid-state materials, gases, liquids, and semiconductor crystals were found possessing laser qualities. Almost every imaginable material was tried in order to produce new and interesting lasers. Even some varieties of jelly brand dessert were announced emitting xenon light, and according to this legend, they are supposed to work fairly well.

In many ways, the laser was a solution looking for a problem. Well, the problems soon followed in great numbers. It would be hard to imagine the modern world without lasers. They are used in everything from CD players to laser printers, fibre-optics and free-space communications, industrial cutting and welding, medical and surgical treatment, holography and light shows, basic scientific investigations in dozens of fields, including Star Wars weapons research. The unique characteristics of laser light make these and numerous other applications possible. In fact, it is safe to say that the vast majority of laser applications have not yet even been suggested.

However, if treated inadequately, an extremely powerful beam of laser light can be a source of destruction. You must never stand in the way of the cutting laser beam. Only by looking directly into the beam or its reflection from a shiny object you can damage your eyes. Besides, laser power supply being typically 2500 V or more, a QUALIFIED person must provide external power supply, as ordinary insulation is not enough. Thus, no matter how advantageous and useful they are, lasers are dangerous. Hence, safety rules must be strictly observed.

12.Provide detailed answers to these questions.

1. What is a laser? What other sources of light do you know?

2. What was the first laser like?

3. Does the laser possess any unusual properties? What are they?

4. When did the laser age begin?

5. Many substances produce laser light, don't they?

6. Were there any surprising discoveries?

7. Why is it difficult to imagine our life without lasers?

8. What are the most common uses of lasers?

9. Why are lasers considered dangerous?

13.Explain what the author means by the following statements.

1. A laser is a source of light but unlike anything that had ever been

seen before 1960.

2. With this invention the laser age was born.

3. According to this legend, they are supposed to work fairly well.

4. In many ways, the laser was a solution looking for a problem.

5. In fact, it is safe to say that the vast majority of laser applications

have not yet even been suggested.

6. If treated inadequately, an extremely powerful beam of laser light

can be a source of destruction.

14.Write two paragraphs, one about advantages, the other about possible

dangers of lasers.

LESSON 12

Scientific Exploration

1. Discuss the following questions.

a) How do scientists explore micro- and macroworlds?

b) What means of scientific exploration do you know?

c) Do you believe we can contact alien civilizations? How?

2.Read and learn the new words, write them down into your vocabulary:

Alien-іноземець

Scanning-перегляд

Interstellar- міжзоряний

Hardly-навряд

Detected- визначений

Maintained- підтриманий

Advanced- прогресивний

Fruitful- плідний

Across- через

Lasting- тривалий

Brief- короткий

Entire-повний

Spot-пляма

Brighter- яскравіше

Distant-віддалений

Practicable-реальний

3. Read the students' conversation and learn about an unusual

application of the laser telescope.

Peter: Pavel, have you heard about artificial stars?

Pavel: Not yet, but I'd like to know about them more, anyway.

Peter: Well, this article says they are created with the help of a laser telescope. One of these experiments is described here.

Pavel: Really? And what was the result of the experiment?

Peter: The reporter claimed that a bright sodium star, as big as about a natural star, had been generated.

Pavel: That sounds fascinating! How was the experiment carried out?

Peter: Oh, it was said in the article that the Solar Vacuum Tower Telescope had launched a 4-watt laser beam to the atmos¬phere and recorded the return light from the generated artificial star at the same time.

Pavel: Why do you think this artificial star has been created?

Peter: Well, there may be other reasons but I'm sure the star will serve as a model for further research of the universe.

Pavel: Oh really? May be in this way we'll be able to establish interstellar communication?

Peter: That's a good idea, but the scientists will have to carry out a number of experiments to prove that.

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