2. Match the notions and their meanings:
nucleon a) a fundamental form of energy observable in positive and negative forms that occurs naturally (as in lightning) or is produced (as in a generator) and that is expressed in terms of the movement and interaction of electrons
nucleosynthesis b) a proton or neutron especially in the atomic nucleus
self-sustaining c) an uncharged elementary particle that has a mass nearly equal to that of the proton and is present in all known atomic nuclei except the hydrogen nucleus
electricity d) the production of a chemical element from simpler nuclei (as of hydrogen) especially in a star
neutron e) the distribution of a quantity (as mass, electricity, or energy) per unit usually of space (as length, area, or volume)
density f) matter composed of antiparticles
antimatter g) maintaining or able to maintain itself
3. Find words which mean the following in the text above:
Verbs
to happen/ take place
to free/ liberate
to take in/ concentrate inside
to operate/ check/ command
to accomplish/ get/ reach to produce/ make
to compel/ to make sth/sb do smth.
to unite/ mix
4. Make a list of collocations with the words below and use them in sentences of your own:
process nuclei
purposes bomb
design charge
repulsion neutron
density process
5. Match the verbs with prepositions, translate and make sentences of your own using these verbs.
t
o
accompany ______
to work ______
to result ______
to generate ______
to put ______
to hold ______
to build ______
2.3. Each group presents its text. The procedure should include the following participants:
2-3 reporters
2 secretaries who write down questions to the text of another group.
TEXT 3
3.1. Before reading the text below complete the sentence below.
The binding energy curve is obtained …
3.2. For questions 1-6, read the text and decide which answer (A, B, C or D) best fits each gap.
Nuclear Binding Energy Curve
The binding energy curve is obtained by dividing the 1____ nuclear binding energy by the number of nucleons. The fact that there is a 2______ in the binding energy curve in the region of stability near iron means that either the breakup of heavier nuclei (fission) or the combining of lighter nuclei (fusion) will yield nuclei which are more 3______ bound (less mass per nucleon).
The binding energies of nucleons are in the 4 _____ of millions of electron volts compared to tens of eV for atomic electrons. Whereas an atomic transition might emit a photon in the range of a few electron volts, perhaps in the visible light region, nuclear transitions can emit gamma-rays with quantum energies in the MeV range.
The iron limit: The buildup of heavier elements in the nuclear fusion processes in stars is 5_____ to elements below iron, since the fusion of iron would subtract energy rather than provide it. Iron-56 is abundant in stellar processes, and with a binding energy per nucleon of 8.8 MeV, it is the third most tightly bound of the nuclides. Its 6______ binding energy per nucleon is exceeded only by 58Fe and 62Ni, the nickel isotope being the most tightly bound of the nuclides.
1 A mixed B entire C total D general
2 A summit B peak C spike D apex
3 A strictly B snugly C compactly D tightly
4 A range B line C row D series
5 A bound B limited C confined D restrained
6 A medium B middle C average D moderate