6. Составьте план к тексту 2.1. Перескажите вкратце содержание текста Mineral Composition and Structure, используя план, а также следующие ключевые слова:

more than that

exceptionally hard

in equal amounts

found in beds

in definite proportion

cooled down

were formed

to illustrate the formation

the resulting solid

a unique crystalline structure

TEXT 2.2.

VOCABULARY WORK:

• Запомните следующие слова:

Научный вокабуляр:

fracture ['frxkCq] - разлом; излом

cleavage ['klJvIG] - отслоение

hardness ['hRdnqs] - твёрдость, прочность; сопротивляемость

lustre ['lAstq] - блеск; отражённый свет

refraction [rI'frxkSn] - преломление, рефракция

double ['dAbl] refraction - двойное преломление

extinction [Ik'stInkSn] - затухание; ослабление; гашение

pleochroism [plI'Okrqu‚Izqm] - многоцветность, плеохроизм

plane [pleIn] - грань

lattice ['lxtIs] - (кристаллическая) решётка

face [feIs] - плоскость, грань (кристалла, алмаза, геометрического тела)

angle ['xNgl] - угол

axis ['xksIs] (мн. число axes ['xksJz]) - ось, осевая линия

twinning ['twInIN] - образование двойников, удвоение

dispose [dI'spquz] - помещать, размещать, располагать, распределять, расставлять

Общеязыковой вокабуляр:

indispensable [‚IndI'spensqbl] - необходимый, обязательный; незаменимый

accomplish [q'kAmplIS] - совершать, выполнять; достигать

bind [baInd] together [tq'geDq] - объединять; объединяться

intersect [‚Intq'sekt] - пересекать, пересекаться

tetragonal [tq'trxgqnql] - четырехугольный, тетрагональный

orthorhombic [‚LTqu'rOmbIk] - призматический; ромбический; трёхмерный

perpendicular [‚pE:pqn'dIkjulq] - перпендикулярный, поперечный

hexagonal [hqk'sxgqnql] - шестиугольный, гексагональный

expansion [Ik'spxnSn] - увеличение (в размере, объёме, количестве)

triclinic [traI'klInIk] - триклинный; агирный

incline [In'klaIn] - наклоняться, склоняться, клониться

exhibit [Ig'zIbIt] - показывать; выказывать, выражать, проявлять

distort [dI'stLt] - искажаться; деформироваться

modification [‚mOdIfI'keISn] - модификация, вариант, разновидность

• Прочтите следующий текст и переведите его:

The Properties of Minerals

Property is a quality, attribute, or distinctive feature of anything, especially a characteristic attribute such as the density or strength of a material. It is indispensable to identify the component minerals of a rock in order to understand its composition. The mineral identification may be accomplished through reference to its physical and chemical characteristics. First of all we are to consider some of the most important physical properties. These are the following: electrical and magnetic properties, crystal form, state of aggregation, fracture, cleavage, hardness, specific gravity, surface energy, taste and smell, and the properties dependent on light, such as lustre, colour, refraction, double refraction, extinction and pleochroism.

It goes without saying that all matter is made up of ions or atoms aggregates linked together in various ways. When bound together in a regular pattern or lattice these ions or atoms assume the crystalline state. There is no need for the crystalline material to have a definite external form, but under favourable circumstances it will solidify as a crystal, or a solid bounded by planes or faces. These planes or faces have definite geometrical relationships which are controlled by the atoms or ions internal planes. These relationships result in the angles between the faces which are fixed and invariable for any one substance and thus have diagnostic value. The relative positions of the crystal faces can be described with reference to crystallographic axes. There may be three or four such axes. The classification of crystals is based on their symmetry in accordance with which they are grouped into five systems:

1. Cubic means relating to or belonging to the crystal system characterized by three equal perpendicular axes. The unit cell of cubic crystals is a cube with a lattice point at each corner (simple cubic) and one in the

cube’s centre (body-centred cubic), or a lattice point at each corner and one at the centre of each face (face-centred cubic).

2. Tetragonal stands for relating or belonging to the crystal system characterized by three mutually perpendicular axes of which only two are equal.

3. Orthorhombic denotes relating to the crystal system characterized by three mutually perpendicular unequal axes.

4. Triclinic signifies relating to or belonging to the crystal system characterized by three unequal axes, no pair of which are perpendicular.

5. Hexagonal indicates relating or belonging to the crystal system characterized by three equal coplanar axes inclined at 60° to each other and a fourth longer or shorter axis at right angles to their plane.

Crystals hardly ever show true geometric symmetry. They are usually distorted by the expansion of some faces at the expense of others. On the other hand the angles between faces remain constant and it is this angular relation that determines the symmetry. The full symmetry of the crystal system is not always exhibited and forms with one-half or one-quarter of the normal number of faces may develop. Another modification of symmetry is twinning (that is to form into a twin), where a crystal is composed of more than one specimen which is symmetrically disposed about a plane known as the twinning plane.

Комментарии к тексту:

the properties ['prOpqtIz] of minerals - свойства минералов

distinctive [dI'stINktIv] feature ['fJCq] - различительный элемент, дифференциальный признак

characteristic [‚kxrIktq'rIstIk] attribute - отличительная черта, характерное свойство;

we are to consider [kqn'sIdq] - мы должны принимать во внимание, учитывать

electrical [I'lektrIkl] and magnetic [mxg'netIk] properties - электрические и магнитные свойства

crystal ['krIstl] form - форма кристалла; кристаллическая форма

state of aggregation [‚xgrI'geISn] - агрегатное состояние (вещества)

specific [spq'sIfIK] gravity ['grxvqtI] - удельная масса

surface ['sE:fIs] energy ['enqGI] - поверхностная энергия

taste [teIst] and smell [smel] - вкус и запах

it goes without [wID'aut] saying ['seIIN] - само собой разумеется

ions [aIqnz] or atoms ['xtqmz] aggregates ['xgrIgqts] - множество ионов или атомов

regular ['regjulq] pattern ['pxtn] or lattice ['lxtIs] - систематическая модель или решетка

crystalline ['krIstq‚laIn] state - кристаллическое состояние

under favourable ['feIvqrqbl] circumstances ['sE:kmstqnsIz] - при благоприятных условиях

solid ['sOlId] bounded [baundId] by planes or faces - твердое тело, ограниченное плоскостями и гранями

definite ['defnqt] geometrical [‚GJq'metrIkl] relationships [rI'leISnSIps] - определенные геометрические отношения

fixed [fIkst] and invariable [In‚veqrIqbl] - постоянные и неизменные

diagnostic [‚daIqg'nOstIk] value ['vxljH] - диагностическое значение

equal ['Jkwql] perpendicular axes - одинаковые перпендикулярные оси

unit ['jHnIt] cell [sel] - элементарная ячейка (кристаллической решётки)

mutually ['mjHCuqlI] perpendicular axes - взаимно перпендикулярные оси

coplanar [kqu'pleInq] axes - расположенный в одной плоскости оси

hardly ['hRdlI] ever ['evq] - едва ли когда-нибудь; почти никогда

geometric symmetry ['sImqtrI] - геометрическая симметрия

at the expense [Ik'spens] of - за счет

on the other ['ADq] hand - с другой стороны

one-half [hRf] or one-quarter ['kwLtq] - половинный или четвертной

the twinning ['twInIN] plane - плоскость двойникования (в кристаллах), плоскость удвоения

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