Exercises

1. Listen, read and translate the text

2. Answer the following questions in a written form;

1. How can many scientific facts be explained? 2. When do molecules exert forces of attraction? 3. When are forces of attraction really large? 4. What substance is a gas? 5. In what state of a substance are all the molecules weakly held together? 6. In what state of a substance will the molecules become closer together?

3. Make up and write 8 sentences using the words given in the table:

Water Liquid Matter Gas

can may must had to

maintain adaapt itself exist be transformed

into steem. in three states. as solid. in nature. its original volume. to the shape of the vessel.

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4. Write 8 sentences, 2 for each pattern:

1. Water can be transformed into ... . 2. A solid body has a definite ... . 3. ... readily alters its, shape and adapts itself to the vessel containing it. 4. It is difficult ... a solid body.

5. Make up sentences using the words given below (e.g. Matter may exist):

(Matter, a gas, one, a (may exist, can change, has

liquid, a solid, any material) a volume, may expand, d does not alter its size, consists

s of matter)

6. Copy these sentences putting "can", "may", "must", "could", "might", "had" in the blanks:

1. He ... be in the laboratory now. 2. We ... easily ob­serve this phenomenon some days ago. 3. Liquids ... trans­mit pressure. 4. They ... come here more often. 5. You ... not speak loudly. 6. You ... to work hard to pass your last examinations. 7. She ... be ill, I am afraid.

7. Find answers to the questions using this table:

Can you bend it? May I transform ice into water? What may it be? Must I study three states of matter?

Certainly, you may. I think it is liquid. Yes, you must. Yes, please. No, you may not. Yes, I can. A piece of wire is soft. No, you needn't.

8. Copy these sentences putting "gas", "can", "shape", "vol ume", "bend", "tools", "destroy", "liquid", "alters" in the blanks:

1. A substance can be transformed from the ... state into the solid. 2. It is impossible to fill half of the bottle with ... as it ... be done with liquids. 3. Milk in a glass has the ... of the glass. 4. Every solid has a definite shape and ... .5. We can ... a glass tube by heating it. 6. You can not break a stone without some special ... . 7. You may ... a glass releas­ing it from your hand. 8. A liquid ... its shape.

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9. Make up and write all possible questions to these sen­tences:

1. The materials around us such as air, water, metals and minerals are forms of matter. 2. Many substances can exist in more than one of three possible states, the state de­pending on the substance itself as well as its volume, tem­perature and pressure. 3. Water can exist as solid (ice), as a liquid and as a gas.

10. Translate the following sentences and explain the use of tenses in them:

1. Much useful work can be done in science without need­ing to know what atoms and molecules are really like. 2. Many physical phenomena cannot be understood properly with­out an appreciation of what makes the atoms of the various chemical elements different from one another. 3. At the turn of the century, however, men learned that atoms could be smashed; and that pieces of matter smaller than atoms can and do exist. 4. In the nineteenth century it became known, that all the material substances of the universe could be con­sidered made from the relatively small number of chemical elements.