1. What scientific discoveries led to the idea ofthe first chain reaction?
2. When and where was the first atomic pile constructed?
3. What fissile material was used in it?
4. What conditions should be met for the chain reaction to be achieved?
5. Could the Fermi-pile be useful as a power source? Why not?
6. What two scientific ideas did the Fermi-pile demonstrate?
• Give a summary of the passage using the scheme on p. 94.
• Choose the correct form to fit into each sentence.
(collisions, collide, colliding)
1. Quite frequently the two types of atom will.... The energy given up by the electron injumpingtoa lower state goes into creating an additional photon with the same characteristics as the ... photon. For samples of a very large size only a small fraction of the neutrons produced in them has a chance to reach the surface before... with one of the nuclei. There are two kinds of... between the electrons and the atoms.
(the question, in question, question)
2. The substance ... contains traces of this element. One might... these results. Ifthe size of the sample ... is less than 10 cm, most ofthe fission neutrons will cross the surface and flyaway.... arises of how accurately these data present the results obtained.
• Translate the following word combinations.
original fission neutrons, nuclear chain reaction, single fission process, vertical cloud chamber, cosmic ray particle, wide energy spread, total energy liberation, thick material layer, critical size level, nuclear power production, ordinary steam turbine
• Translate into Russian, observe the use of "theformer, the latter".
1. There are two different methods to count scintillations: in the former the microscope is used, in the latter, the Geiger-counter.
2. There are two ways to detect and measure radioactivity. The former is the gold-leaf electroscope, the latter, the Wilson cloud chamber.
3. Only two types of rays are deflected in the magnetic field: the former to the left, the latter to the right.
CLASSWORK
READING (12B)
• Skim the passage as fast as possible and find answers to the following questions.