Chairman: Good afternoon, dear colleagues and our guests – the correspondents of different newspapers! We start our press conference. It is devoted to the latest discoveries of our laboratory X. You can see the greatest scientists here. Let me introduce them: Mr Petrov, Mr Ivanov, Mr Alexandrov, Mrs Pospelova, Mrs Guralevich. They are ready to answer your questions.

Mr Brown: I’d like to ask you a question. "Daily Telegraph” newspaper. I heard that your laboratory invented a device for measuring temperature of water. What have you to tell us?

Chairman: Mr Petrov has the floor.

Mr Petrov: The problem was to find whether any liquid is cold or hot. The following experiment shows how easy it is to be mistaken. We have three glasses (glass 1 contains cold water, glass 2 – very hot water, glass 3 – water at room temperature). Will you help me, please, Mr Brown? Could you come here, please? Will you put a finger of your right hand into glass1, and a finger of your left hand into glass2? Half a minute later put the finger from glass1 into glass 3. Is it cold?

Mr Brown: No, it’s warm.

Mr Petrov: And now put the finger from glass 2 into glass 3. Is it cold?

Mr Brown: Yes, it is very cold.

Mr Petrov: But the water in glass 3 is neither cold nor hot. The water in glass 3 is at room temperature. We worked hard and now we can say we’ve made a wonderful device for measuring temperature. And we called it a thermometer. If we use a thermometer we won’t be mistaken.

Mr Brown: Thank you.

Mr Sidorov: Could you answer my question?

Chairman: Yes, do please.

Mr Sidorov: "What’s New In the World?” magazine. It is known that water boils at 100 degrees Celsius. What are your achievements in this field of science?

Chairman: Mrs Guralevich can answer your question.

Mrs Guralevich: I won’t tell you about the details of our experiments but the result is unforgettable. We discovered that even cold water can boil. Do you believe it or not? My lab assistant can show boiling of cold water. We have a glass of water and a wet handkerchief. The wet handkerchief is put on the glass and the centre of the handkerchief is pushed down. Then the glass is turned upside down on the right hand, and the lab assistant takes the glass with his left hand. When the assistant puts his finger on the glass, the water will boil! You can even hear the noise of the boiling water!

Picture 1

Mr Sidorov: Oh, it’s unbelievable! Thank you!

Mr Kozlov: "Good Morning!” newspaper. Well, I’m interested in the problem of ice on the pavements and roads in big cities. Have you solved this problem?

Chairman: Our laboratory X experts are glad to state that they invented a very simple method of solving this problem without using very expensive equipment. And we can prove it with this simple experiment. Mrs Pospelova is ready to show you this experiment.

Mrs Pospelova: We put an ice cube into the glass of water. We have a piece of string 10 cm long. First we put the string across the piece of ice, then we put some salt on the ice. The ice will melt. Some moments later the water on the ice cube will freeze.

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And we can raise the piece of ice! This experiment shows that you should use much salt to melt ice near the door of your house. If you don’t put enough salt, the water will freeze again.

Mr Kozlov: Thank you for the useful advice.

Mr Johnson: Well, let me ask a question!

Chairman: Yes, please!

Mr Johnson: "Inventions In Science” magazine. There is some information about your laboratory X investigations in physics. Could you tell us about them?

Chairman: Mr Ivanov has the floor.

Mr Ivanov: You are right. Our laboratory work at some problems in optics. That is illusion. One of the most interesting of all natural illusions is the large size of the full moon when we see it low on the horizon.

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Six hours later when the moon is high in the sky, we think that it has become much smaller. But photographs show that the diameter of the moon is the same. Our version of this illusion is that the moon on the horizon looks larger because we can see it together with some trees or houses (which are on the horizon too). Unfortunately nowadays we can’t explain this illusion at sea where there is nothing on the horizon. This problem should be solved.

Mr Johnson: Thank you.

Mr Brown: "Daily Telegraph” newspaper. What other problems in optics do you try to solve?

Chairman: Mr Petrov has the floor.

Mr Petrov: The next phenomenon we work hard at is a strange spiral. You can see a picture.

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You are sure that the spiral line starts in the centre. But if you try to follow the line with a pencil, you’ll find that it is not a spiral. You have a number of concentric circles. So our scientists try to solve this problem.

Now we are going to show you a very interesting experiment. We have a square piece of cardboard four by four centimeters. There is a picture of a fishbowl on one side of the square and a picture of a small fish on the other side. There are two holes and short pieces of string (as shown in the picture).

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I am holding the pieces of string with the fingers of my hands. Now I can turn the square very quickly with my fingers or with any other turning device. When it is turning you’ll see only one picture of the fish inside the fishbowl.

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Our experts think this experiment proves that our eyes can keep a picture of a thing for half a second after you have put that thing away.

Mr Brown: Thank you.

Mr Hammer: I’ve got a question.

Chairman: Would you like to ask your question?

Mr Hammer: "Today” newspaper. My question deals with a phenomenon in optics. Once I put a stamp under the glass of water. And when I put a saucer on the glass, I couldn’t see the stamp! How can your scientists explain this phenomenon?

Chairman: I think Mr Alexandrov can do it.

Mr Alexandrov: To my mind the explanation lies in the phenomenon of refraction. The rays of light bend when they pass at an angle from water to air. The lines in Picture show the refraction. There is no angle from which you can see the stamp. Here we can show you the experiment.

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Mr Hammer: Thank you for your explanation.

Mr Zhukov: Let me ask a question!

Chairman: Certainly. You’re welcome.

Mr Zhukov: The "Vedomosti” newspaper, Saint Petersburg. Some years ago a television operator turned a large wheel of this sort (shows a picture).

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And people who were watching his TV programme saw the colours quite clearly on their black-and-white television screens. Do your scientists work at this problem and can they give any explanations of this phenomenon? I’ve got a circle of a certain sort on the cardboard. Could we watch this phenomenon just now?

Chairman: Of course we can (the phenomenon is shown). And now I think Mrs Guralevich can tell us something about this phenomenon.

Mrs Guralevich: Well, I should say that our scientists were interested in this phenomenon and they began their work two years ago. The work hasn’t been finished yet and we think that the results of our work can be declared in some years.

Mr Zhukov: Thank you very much.

Chairman: I’d like to give you a problem to think and to have fun. I want to show you a picture.

Picture 9

Will you answer the question? Where is the missing piece of cake? Let’s brainstorm! Each of you can have a picture. Any ideas?

(People who are present at the conference start brainstorming. If anybody finds a solution of this problem this person can be given a prize. Solution: you should turn the picture upside down).

Chairman: Well, I think our time is up. Thank you for your questions and attention. We hope you are quite satisfied with it. If you have more questions you can give them in the written form. Our conference is over.