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

21.	light	A.	to gain knowledge of something
22.	to predict	B.	very small
23.	to find out	C.	electromagnetic radiation that is capable of causing a visual sensation
24.	wave	D.	to emit a steady even light without flames
25.	to detect	E.	consisting of matter all through
26.	tiny	F.	to discover the existence or presence of something
27.	vacuum	G.	to give off radiation or particles
28.	to glow	H	to make a declaration about something in advance
29.	solid	I.	a region containing no matter
30.	to emit	J.	any undulation on or at the edge of a surface
		K.	to make or become greater in size
		L.	the process of change in the physical position of an object

Supplementary Tasks :

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

1.… Maxwell made the brilliant deduction … (line 1)

A. induction B. conclusion C. statement

2.He also predicted that … (line 3)

A. suggested B. forecasted C. warned

3.… the sparks would send out waves of electromagnetic radiation. (line 6)

A. emit B. oscillate C. generate

4.… they might not be visible like light. (line 7)

A. distinguished B. found C. seen

5.… the spark was a stream of tiny quick bits of atoms … (line 17)

A. huge B. C. minute

6.… the discharge tube helped Wilhelm Roentgen to discover another kind of radiation. (line 20)

A. find B. distinguish C. develop

7.… it could not stop these new mystery rays …(line 23)

A. beams B. signs C. sparks

8.... radiation might be emitted not only by electricity … (line 26)

A. absorbed B. released C. transmitted

9.Marie and Pierre Curie soon found the intensity of radiation … (line 34)

A. increase B. input C. strength

10.… in exact proportion to the amount of uranium. (line 34)

A. quantity B. volume C. sum

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

A.Radioactivity is described to be the most important discovery in physics.

B.Rays have been intensively investigated all over the world since the eighteenth century.

C.Different types of radiation became a great discovery.

D. To understand the way rays behave many famous scientists made a great effort.

E.Many American scientists did their best to explain the phenomenon of radiation.

TEXT 5

THERMODYNAMICS

(1)Heat behaves in a predictable way. For example, when ice is placed in hot water, it melts. Heat – and other forms of energy – obeys "laws" that restrict its behaviour, and the study of heat as a form of energy is called thermodynamics. The “Laws of thermodynamics” were worked out during the mid-19^th century. The "law of conservation of energy" says that energy cannot be created or destroyed, but it can only change from one form to another. This is the first law of thermodynamics. (2)Any form of energy can be converted entirely into heat. But when heat energy is changed into other forms, it can never do so entirely. Some of it always remains as heat, and temperatures always even out. This is the second law of thermodynamics. The behaviour of heat energy can be explained by the fact that it is the motion of particles of matter – atoms and molecules. The temperature of matter is the average energy of all its particles. Conduction, the transfer of heat between matter in contact, happens because the particles of a hot object transfer some of their energy to those of a cooler object. (3)No machine can ever be 100 per cent efficient because a certain amount of energy will always be lost as heat. This means that there can be no such thing as a perpetual motion machine, which would work forever and never run out of energy, but many people still try to make one. (4)This attempt was built in 1747. Iron balls fell on to a large wheel and turned the wheel around to operate the diagonal screw. The screw would then lift the balls up to repeat the process perpetually. But in practice the machine did not work because it would eventually slow down to a halt as its energy was lost as heat. (5)A variation of the vacuum flask invented by the Scottish physicist James Dewar was mass-produced in the early 20^th century and sold under the trade name Thermos. The flask contains a partial vacuum between its walls that greatly reduces conduction, the transfer of heat energy between matter in contact. Heat energy can become radiation and can pass between particles, even in a vacuum, but the vacuum flask has silvered walls that reflect radiated heat.