Words and word combinations to be remembered

shape – форма	solid – твёрдое тело, твёрдый	rebound – отскакивать, отлетать
pressure – давление	collide – сталкиваться, соударяться	volume – объём
forces of attraction – сила притяжения	knock – стучать, ударять	occupy – занимать
space – пространство, место, площадь	evaporate – испарять, испаряться	property – свойство
path – траектория	escape – улетучиваться	resist – сопротивляться, противостоять
liquid – жидкость, жидкий	reduce – ослаблять, понижать, сокращать	fill – наполнять

Ex. 1. Translate from Russian into English:

Газ, жидкость, твердое тело, форма, сосуд, направление, скорость, объем, сталкиваться, сила притяжения, среднее расстояние, определенное пространство, механическое сопротивление, свойство, вещество, давление, молекула, положение дел, отскакивать, испаряться, замерзнуть, ослабнуть, взад вперед.

Ex. 2. Make up the word combinations using the words from 2 columns, make up some sentences with these word combinations:

Exert	into contact
Take up	in all directions
Move	a definite space
Occupy	any effort
Resist	a pressure
Become	some fixed shape
Come	closer

Ex. 3. Fill in the blanks:

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’s difficult … a solid body.

5. A substance can be transformed from the … state into the solid.

6. It is impossible to fill half of the bottle with … as … be done with liquids.

7. Milk in glass has the … of the glass.

8. Every solid has a definite shape and … .

9. We can … a glass tube by heating it.

10. You can not break a stone without some special … .

11. You may … a glass releasing it from your hand.

12. A liquid … its shape.

Ex. 4. Answer the following questions:

1. In what states may matter exist? 2. When do molecules exert forces of attraction? 3. When are forces of attraction really large? 4. What substance is a gas? 5. What does a solid body have? 6. What does a liquid readily alter? 7. What does a liquid maintain? 8. In what state of a substance are all the molecules weakly held together. 9. In what state of a substance will the molecules become closer together?

Ex. 5. Say a few words about:

• the gaseous state

• the liquid state

• the solid state

• the forces of attraction

Unit 5. The fundamental physical constants

Contrary to popular opinion, physics is usually not a very exact science. A physicist is often quite pleased with himself if he measures some property of matter to an accuracy of within a few percents and finds that his measurement agrees with a theoretical prediction, again to within a few percents. This comparative lack of precision arises from two main sources. First, most experiments deal with a complex system in which a variety of interrelated and often poorly understood phenomena are involved. Second, the pertinent theory usually provides only an approximation based on a simplified conceptual model of the system.

There are, on the other hand, a few special quantities in physics that can – indeed must – be known to a much greater accuracy. These are the fundamental physical constants. They include such quantities as the speed of light in a vacuum (c), Planck's constant (h), the charge of the electron (e), the mass of the electron (me) and the fine-structure constant (a). The speed of light in vacuum is a universal physical constant important in many areas of physics. Its value is 299,792,458 metres per second. The Planck constant is a physical constant reflecting the sizes of energy quanta in quantum mechanics. The fine-structure constant is a physical constant characterizing the strength of the electromagnetic interaction. Being dimensionless quantity, it has constant numerical value in all systems of units.

Why is it important to know the numerical values of the fundamental constants with great accuracy? First of-all, the quantitative predictions of the basic theories of physics depend on the numerical values of the constants that appear in the theories. An accurate knowledge of these values is therefore essential if one hopes to achieve an accurate quantitative description of the physical universe. More important, the careful study of the numerical values of these constants, as determined from experiments in the different fields of physics, can in turn test the overall consistency and correctness of the basic theories of physics themselves. If one looks at the entire structure of physics, one sees a vast array of apparently divergent fields: solid-state physics, atomic physics, nuclear physics, elementary-particle physics and so on. The unifying force that binds all these fields together is theory; the basic concepts contained in quantum mechanics, electromagnetic theory, special relativity and so forth are present in all of them. The fundamental constants are the quantitative links that “binds physics together”.