Transcript UNIT 2 CLASSIFICATION
UNIT 1
MATERIALS
• • • •
Vocabulary
Names of materials Characteristics of materials Adjectives and dimensions Word formation: SUFFIXES to form ADJECTIVES
• • •
Grammar and functions
Giving definitions & describing Articles Expressing measurements
VIDEO
SECTION 1 : elements found in all stars.
Profile of the abundance of elements found in stars:
-immense amounts of
HYDROGEN
and
HELIUM
.
• • • • •
-
LOWER
amounts (
2
%) of the heavier elements • Peaks
CARBON OXYGEN MAGNESIUM SILICON SULPHUR IRON
VIDEO
• • • • •
Process: nuclear fusion 2 HYDROGEN atoms= ENERGY -> SUNLIGHT HELIUM + HELIUM + HELIUM HELIUM + CARBON OXYGEN + HELIUM Right up to IRON = CARBON = = OXYGEN MAGNESIUM
•
For each of these fusion reactions to occur, INCREASING TEMPERATURE and PRESSURE are needed
• • • • •
DESCRIPTIONS
Graphite
: a blackish soft allotropic form of (0) carbon, with (0) metallic luster and (0) greasy feel. It consists of layers of carbon atoms. Unlike (0) diamond, (0) (0) graphite is coatings and (0) electrodes, as a nuclear reactors, and, in an a electrical conductor . It is carbon fibre form, material for (0) sporting equipment lubricant, as as a a used in (0) moderator in pencils, (0) tough lightweight
Ceramics
: A ceramic material may be defined as an oxide material. It is solid and inert. (0) inorganic crystalline Ceramic materials are brittle, hard, strong in (0) compression, weak in (0) withstand (0) very high temperatures tension. (0) Ceramics can generally
Nylon
is a thermoplastic, silky material made of repeated units of amide bonds. It is very strong and elastic. It is used to make (0) fabrics, (0) ropes , (0) musical strings, and for (0) mechanical machine components
Petrol
is
a
volatile flammable liquid. It consists of hydrocarbons. It is used as
a
fuel especially in (0) (0) short-chain internal combustion engines and as a solvent
Plastics:
(0)
a
plastic substance is any of the processed materials polymers of (0) consisting of high molecular numerous organic synthetic or (0) very large molecules that are mostly
weight
and can be made into (0) objects, (0) films, or (0) filaments
• • • • • • • • • • • • • •
LISTENING: what is a metal?
We are so familiar with metals that it might be quite a surprise to be asked the question: What is a metal?. Take magnesium for example. It burns easily . Why then do we regard magnesium as a metal similar to say iron which will not burn ?
The most important properties that distinguish metals from non-metals are: they reflect light and thus are shiny They are good conductors of heat and electricity They combine with fluorine and chlorine Most react with acids and with oxygen Apart from these similarities, metals show a great deal of variation. Gold, lead and sodium are very soft materials, much softer for example than silicon and graph ite, both non-metals. Many metals corrode easily . Gold, chromium and platinum , however, do not. Some metals are very active: sodium, calcium and potassium combine easily with oxygen, chlorine and fluorine . Gold, silver and mercury , on the other hand, do not form compounds so easily.
Metals far outnumber non-metals: only 20 of the 103 elements known today are non-metallic
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2.
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5.
6.
ARTICLES (1)
...Ø...
petrol is used as engines.
..a.
fuel in .. Ø..
combustion .... Ø...
corrosion is ...a...
very serious problem in Ø.
metallic structures.
.. Ø..
iron is used in ... Ø. engineering due to ...its..... strength.
....the.. physical properties of .... Ø.
studied in Ø chapter 3.
matter will be There are many energy sources, like ...Ø...
...Ø...
coal oil or Ø fission is one of ....the..
reactions which release Ø two types of Ø nuclear large amounts of Ø energy. The fission of Ø Uranium atoms is used in Ø nuclear power plants to generate Ø electricity.
ARTICLES (2)
7. The/a major component of Ø steel is Ø iron, a metal that in its pure state is not much harder than Ø copper.
8. A generator is a machine which produces Ø electricity 9. Ø silicon is used as a manufacture of Ø semiconductor in chips.
the 10. Ø plastics may be classified into two major groups according to their chemical composition.
11. Ø mathematics is basic for an engineer.
12. An alloy is a metallic substance composed of two or more elements as either a compound or a solution.
13. In Ø Kevlar, an artificial fiber, straight, giving it Ø/its the molecules lie strength and Ø/its stiffness
ARTICLES: MERCURY
Ø mercury is a/the chemical element whose symbol is Hg.
It is a silvery-white, heavy, liquid metal. Compared with other metals, it is a heat and a fair conductor of Ø poor conductor of electricity. Ø Ø mercury is the only common metal that is ordinary temperatures. a liquid at Ø It easily forms Ø alloys with many other metals. When it combines with certain metals (such as Ø zinc or Ø tin), the resulting alloy is called an silver, Ø amalgam. Both the element and Ø poisonous. most of its compounds are Ø mercury and its compounds are used in Ø cells, Ø dentistry, Ø thermometers, Ø electrolytic batteries, and in Ø medicine.
DESCRIBING
• • • •
Definition
:
Composition
: It is made (up) of It consists of It has It is composed of It is formed by X is GENERAL CLASS Materials Substances Components Parts Pieces
Characteristics:
To be To look To seem To become + ADJ + ADJ +ADJ + ADJ Shape (circular, elliptical) Properties (flexible, tough) Colour (blue, greenish) Texture (hard, smooth) + NOUN Temperature (warm, cold) Dimensions (long, thin, small) To have
Applications:
X is used for (+GER) / to (+INF) X is used in/as (+NOUN) X serves to (+INF)
VOCABULARY: Adjectives
TEMPERATURE: Boiling, Molten, Cool, warm, Burning, Icy TEXTURE: rough, hard, smooth, soft, sticky SHAPE: rectangular, straight, cylindrical, square, rounded, sharp COMPOSITION: metallic, wooden, plastic, ferrous, synthetic, organic SIZE: huge, tiny, minute, large, broad, short COLOUR: light, bright, dark, opaque, faded, reddish
WORD FORMATION: Adjectives
ADJECTIVES FROM NOUNS LATIN ORIGIN OR ROOT
-IC atomic -AL/AR usual/linear -OUS poisonous/ lustrous
ENGLISH ORIGIN
-FUL beautiful -LESS harmless -(L)Y sunny -ISH yellowish
ADJECTIVES FROM VERBS
-ING shining -ED concentrated -IVE
ADJECTIVES FROM VERBS OR NOUNS (usually from a Latin origin)
-IBLE/ -ABLE -ENT / -ANT terrible/drinkable different/important massive
WORD FORMATION
STAINLESS STEELS
•
StainLESS
steels contain chromium, nickel • and other
alloyING
elements • that keep them rust
resistANT
• in spite of the action of moisture or
corrosIVE
acids and gases. • Some steels have
unusUAL
strength.
• Because of their
shinY
surfaces • architects
wideLY
use them • for
decoratIVE
purposes
.
• • • • • • • • • • • • • • • • •
VIDEO: METEORITES
The Ballwell meteorite fell in 19
65
.
BROWN METALLIC
skin due to
ATMOSPHERIC HEATING
it consists of :
SILICATES
....... (..
GREEN
....olivine) some..
IRON
)
METAL
(
BROWN DISCOLORATION DUE TO OXIDATION OF
chondrules Section of a chondritic meteorite: chondrules
SILICATES
.....(
OLIVINE
........)
DARK
............patches(
IRON METAL
.........) Iron meteorites: Blades
OF IRON-NICKEL ALLOY (IRON WITH A LITTLE NICKEL ) INCLUSIONS OF IRON SULFIDE
......
Meteorites contain three principal phases: 1-
OLIVINE (MAGNESIUM SILICATES
) 2-
IRON OFTEN WITH A LITTLE NICKEL
3-
IRON SULFIDE
...........
Chondritic meteorites appear to have changed chemically the least since their condensation from the primitive solar nebula. They contain
HYDROGEN
and
HELIUM
but otherwise their element abundance should be similar to the abundance in the solar spectrum.
LISTENING: Temperatures
• The most commonly used metal in industry is
IRON
. Its symbol is
Fe
, its atomic weight
55.19
and its specific weight is
7.86 GR/CM3
. Its melting point is
1,528ºC
; this is a metal which is magnetized quite strongly but above
768ºC
it cannot be magnetized.
• Another metal of a great importance in engineering is
ALUMINIUM
, with an atomic weight of
26.97
, a specific weight of
2.7 GR/CM3
and its melting point is
658ºC
• Among metals,
LEAD
is the metal which possesses the highest density, with an atomic weight of
207.22
and a specific weight of
11.34 GR
/
CM3
; contrarily to other metals, however, its melting point is relatively low as it melts at
327ºC
.
LISTENING: Temperatures
• However not all metals have the same characteristics; as an example we have
MERCURY
which is
A LIQUID
at room temperature; thus, the temperature at which this metal changes from liquid to solid is
–38.9ºC
and its boiling point is
357.2ºC
.
• Non-metals, on the other hand, vary greatly with regard to their characteristics. For example,
CHLORINE
has a specific weight of
0.0032 GR/CM3
and its boiling point is
–33.7ºC
. However,
SILICON
, whose specific weight is
2.33
, melts at
1,310ºC
and boils at
2,355ºC
.
•
DESCRIBING
Dimensions:
–
General dimensions
(thin, long, small) –
Specific dimensions
X is 3m+ADJ (long) X is 3m+IN+NOUN (in length) X has a +NOUN + OF 3m ( ´X has a length of 3m) The NOUN+OF X is 3m (The length of X is 3m)
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EXERCISE: Measurements
The film coating the piece must be very
THIN
. It should be 0.05 mm
THICK
The light travels along
THE LENGTH
of the optical fibre In this part of the swimming pool you can dive in because it is 5 ft
DEEP
to the bottom The engineers have built a new tower which is 50 m
HIGH
To make chips, a single crystal in the shape of a long bar of about 10 cm
IN
diameter is cut into circular slices 1/2 mm
THICK
The beams needed for the structure must be 3 m
LONG
and 25 cm
THICK/WIDE
To take the recordings, the thermometer was placed at a
HEIGHT
of 1.5 m above ground level.
8.
9.
EXERCISE: Measurements
The steel bar can resist up to 305 kg IN WEIGHT before breaking The piece of the machine is too long to fit in the slot, so we must make it SHORTER 10. 3-D objects have three main dimensions: HEIGHT , WIDTH and LENGTH 11. The WIDTH of the tunnel decreases as it goes through the mountain, leaving only one lane.
12. The reaction produces a layer on top of the solution, with THICKNESSES ranging from 0.2 to 0.6 mm 13. Pitting is a corrosion process that creates holes of about 0.03 mm DEEP/WIDTH on the surface of the metal 14. HOW WIDE/WHAT WIDTH Well, it is 1/2 m WIDE is the base of the column?.
LISTENING: Dimensions
• •
CHARACTERISTICS OF THE ALLOY
:
Stands very high and very low temperatures melting point = 3,527ºC , below 58ºC
• • • •
DIMENSIONS
:
2.35m high , width =37 cm 1.55m length of its base – it weights 782 kg 1.05cm top
• •
PERFORMANCE
:
1700 hours 350 rpu (revolutions per unit)