М. М. Кутепова The World of Chemistry Мир

What do you think of the discovery? Is it possible? Prove that.

6. 
   Listen to the dialogue again and develop it by using the expressions of surprise, emphasis, certainty and request. Act the dialogue with your partner in front of your fellow students.
   

68

6. 
   Work in pairs and make up a dialogue out of the text below. Act your dialogue in front of your fellow students. There are a few possible situations where your dialogue could take place:
   

1. 
   Two students are discussing the lecture they’ve just heard.
   
2. 
   A student discusses his/her paper with the supervisor.
   
3. 
   At the examination the professor asks the student a few questions on the states of matter, and the student answers.
   

Matter can occupy three different states — gas, liquid and solid. Changes of state depend on the motion of sub-microscopic particle's. The motion of these particles depends on energy. Cooling particles takes away energy and slows them down. Heating particles adds energy and speeds them up. In a gas these particles move quickly and randomly, they have neither set volume nor shape. In a liquid the particles slow down and clamp together. We use gases, such as a natural gas, in many important ways. Cooling a gas into a liquid decreases its volume dramatically. This makes it possible to store and transport it more effectively. In a solid particles of matter have a definite volume and shape. They are held in a pattern that repeats itself in three dimensions. Crystals are highly ordered form of solid matter. They were one of the first clues to the arrangement of particles in the solid state.
The states of matter are few. But the ways in which they are realized, the number of different substances around us, are many. Let me give you an example. On breathing oxygen — the life-giver — is obviously a gas. But here is another element, sulphur, that chemically very closely related to oxygen. And yet, it is obviously different: it is a solid at room temperature. Now, there are obviously different forces that work between the atoms of molecules of sulphur and oxygen within these two substances. We want to know why this is so. We have to probe deeper, we have to, then, ask: What is the nature of the atom? What is it that makes oxygen and sulphur similar or different?

6.