Task 3.11. Read the text and retell it.

Roentgen

In 1895 a German professor Wilhelm Konrad Roentgen discovered a new kind of invisible rays. These rays could pass through clothes, skin and flesh and cast the shadow of the bones themselves on a photographic plate. You can imagine the impression this announcement produced at that time.

Let us see how Roentgen came to discover these all-penetrating rays. One day

Roentgen was working in his laboratory with a Crookes tube. Crookes had discovered that if he put two electric wires in a glass tube, pumped air out of it and connected the wires to opposite electric poles, a stream of electric particles would emerge out of the cathode (that is, the negative electric pole).

Roentgen was interested in the fact that these cathode rays made certain chemicals glow in the dark. On this particular day Roentgen was working in his

darkened laboratory. He put his Crookes tube in a box made of thin black cardboard and switched on the current to the tube. The black box was lightproof, but Roentgen noticed a strange glow at the far corner of his laboratory bench. He drew back the curtains of his laboratory window and found that the glow had come from a small screen which was lying at the far end of the bench.

Roentgen knew that the cathode rays could make the screen glow. But he also knew that cathode rays could not penetrate the box. If the effect was not due to the cathode rays, what mysterious new rays were causing it? He did not know, so he called them X-rays.

Roentgen placed all sorts of opaque materials between the source of his X-rays and the screen. He found that these rays passed through wood, thin sheets of aluminium, the flesh of his own hand; but they were completely stopped by thin lead plates and partially stopped by the bones of his hand. Testing their effect on photographic plates he found that they were darkened on exposure to X-rays.

Roentgen was sure that this discovery would contribute much for the benefit of science. Indeed, medicine was quick to realise the importance of Roentgen's discovery. The X-rays are increasingly used in industry as well.

Task 3.12. There is a competition among citizens of your town for the best name of a new street. You are sure that the street should be named after a scientist. Try to convince the jury in it. In your speech present information on:

1) The name of the scientist you’d like the street to be named after.

2) Where and when he/she was born and worked.

3) The field of science this scientist worked in.

4) The discovery or invention he/she made.

5) Where the results of his/her work are used now.

6) Why you have chosen this very scientist.

Task 3.13. Speak about any great scientific discovery.

Task 3.14. Pretend you are an inventor. Here is your chance to make you own invention. Describe you invention. What does it look like? What does it do? How does it work? Add drawings or a diagram if you wish. Your invention can be funny or serious.

Task 3.15. Read the following dialogues. Reproduce them in pairs.

D I A L O G U E S

Dialogue I

A. Whom was an automobile invented by?

B. An automobile was invented by Benz.

A. When was it constructed?

B. The first automobile was constructed in 1855.

A. What country was it built in?

B. It was built in Germany.

Dialogue II

A. What is known as a diode?

B. The simplest tube with two elements is known as a diode.

A. How are these elements called?

B. They are named a cathode and an anode.

A. Where are diodes used?

B. The diodes are used as detectors, as rectifiers and as switching devices.

Dialogue III

A. Can you tell how many generations of computers are known today?

B. Certainly, I can. Five generations are known today.

A. Do you know what tubes were used in the first generation?

B. Let me think... It was based on vacuum tubes. Am I right?

A. Certainly, you are.

Date: 2016-04-22; view: 1259