IV. Match (21-30) with their definitions (A-L). There are two definitions that you do not need to use.

21.	to rub	A.	rate of recurrence
22.	attraction	B.	the tangible matter of which a thing consists
23.	to investigate	C.	a momentary flash of light
24.	substance	D.	to keep or accumulate for future use
25.	charge	E.	a force by which one object attracts another
26.	to store	F.	to continue in existence after something happened
27.	spark	G.	to move something with pressure against a surface
28.	to survive	H	the property of attraction displayed by magnets
29.	magnetism	I.	the total amount of electricity
30.	circuit	J.	to inquire into a problem thoroughly
		K.	a complete path through which an electric current can flow
		L.	to make or become greater in size

Supplementary Tasks:

I. For statements (1-10) choose the best alternative (A, B or C) to replace the expressions in italics:

1.The word “electricity” comes from “elektron” … (line 6)

A. originates B. begins C. arises

2.… amber attraction was considered a minor curiosity. (line 7)

A. major B. junior C. marginal

3.In the 18th century scientists such as … (line 9)

A. experimenters B. intellectuals C. academics

4.… Stephen Gray began to investigate electricity. (line 10)

A. inquire B. research C. inspect

5.… that various substances could conduct … (line 11)

A. similar B. different C. distinct

6.… rubbing two similar substances together … (line 12)

A. identical B. correspondent C. different

7.The charge could even be stored in a special glass jar … (line 16)

A. bound B. caught C. accumulated

8.... then suddenly let out via a metal chain … (line 17)

A. emitted B. transmitted C. produced

9.People were so excited by Franklin’s discovery … (line 22)

A. invention B. transformation C. finding

10.… machines could be built to generate large quantities of electricity. (line 35)

A. elaborate B. produce C. oscillate

II. Determine the key message of the text. Choose the best alternative (A, B, C, D or E):

A. In the eighteenth century physicists proved energy to be one of the most important phenomenon in nature.

B. Electric and magnetic effects are closely interrelated.

C. Great discoveries concerning electricity proved its importance.

D. Energy is known as the fundamental power which holds everything together.

E. Attractions and repulsions are two demonstrations of electricity.

TEXT 14

THE STRUCTURE AND PROPERTIES OF MATTER

(1)Matter in bulk comprises particles that may be said to be at rest, but the motion of the molecules that compose matter, which is attributable to its temperature, is equivalent to travel at the rate of hundreds of metres per second. (2)Although matter is commonly considered to exist in three forms, solid, liquid, and gas, a review of the effects of radiation on matter must also include the mention of the interactions of radiation with glasses, low–pressure gases, plasmas, and matter in states of extraordinarily high density. A glass appears to be solid but is actually a liquid of extraordinarily high viscosity, or a mixture of such a liquid and embedded microcrystalline material, which unlike a true solid remains essentially disorganized at temperatures much below its normal freezing point. Low-pressure gases are represented by the situation that exists in free space, in which the nearest neighbour molecules, atoms, or ions may be centimetres apart. Plasmas, by contrast, are regions of high density and temperature in which all atoms are dissociated into their positive nuclei and electrons. (3)The capability of analyzing and understanding matter depends on the details that can be observed and to an important extent on the instruments that are used. Bulk matter is detectable directly by the senses supplemented by the more common scientific instruments, such as microscopes, telescopes, and balances. (4) It can be characterized by measurement of its mass, weight, but most commonly by optical phenomena — by the visible or invisible light (i.e. photons) that it absorbs, reflects, or emits or by which its observable character is modified. Energy absorption, which always entails some kind of excitation, and the opposed process of energy emission depend on the existence of ground-state and higher energy levels of molecules and atoms. (5)Excitation to energy levels above those of the energetically stable molecules or atoms may result in dissociation or ionization. Atomic nuclei themselves may exist in various states in which they absorb and emit gamma rays under certain conditions, and, if the nuclei are raised to, or by some process left in, energy states that are sufficiently high, they may themselves emit positrons, negatrons, alpha particles, or neutrons (and neutrinos) or dissociate into the nuclei of two or more lighter atoms. The resulting atoms may be similarly short-lived and unstable, or they may be extremely long-lived and quite stable.