UNIT 2CLASSIFICATION

Vocabulary • Materials: countable vs uncountable nouns

(i.e. general vs specific) • Revision of names of materials

Grammar and functions• Expressing classification• AS, HOW and LIKE• Introduction to connectors

CLASSIFICATION OF MATERIALS

• ACCORDING TO THE STATE OF MATTER • SOLIDS, e.g. COPPER • GASES, e.g. CARBON DIOXIDE • DIVIDE MATERIALS INTO METALS AND NON-

METALS • DEPENDING ON WHETHER THEY ARE PURE

METALS • ALLOYS, e.g BRONZE • METALS CAN BE CLASSIFIED INTO• IRON AND ALL OF ITS ALLOYS • LEAD, GOLD OR MERCURY

CLASSIFICATION OF MATERIALS• CERAMICS, PLASTICS, COMPOSITES, RUBBER • PLASTICS, …, CAN BE DIVIDED INTO • THEIR MOLECULAR STRUCTURE CHANGES • AS MANY TIMES AS NEEDED• ELECTRICAL CONDUCTIVITY • CONDUCTORS, INSULATORS AND SEMICONDUCTORS • THEY PERMIT AN ELECTRIC CURRENT TO FLOW • MOST METALS • LIKE CARBON OR SALT WATER• PLASTICS AND CERAMICS ARE INSULATORS • SILICON • ACT AS CONDUCTORS OR INSULATORS • IN MANY DIFFERENT WAYS

CLASSIFYINGGENERAL CLASS

classified divisionsdivided groupsgrouped into types

is/are arranged classesmay be categorized categoriescan becould be classified

categorizedclassed as solids, liquids or gasesgrouped

IncludesContainsconsists ofis made up ofis formed byis composed ofcomprises

CLASSIFYING SPECIFIC ITEM

classedis classified as GENERAL CLASS

categorized

is put intofalls into the class / category of GENERAL CLASS belongs to

is an example (type, kind, form ....) of GENERAL CLASS

IN many / different / various WAYS

CLASSIFYING

Basis of the classification

criteriaaccording to characteristicson the basis of the following featuresdepending on properties

whether (+ CLAUSE)

COMPLETE THE TABLE

Engineering materials

non-ferrous

lead

thermoplastics

plastics

non-metalsmetals

ferrous ceramics

gold mercury

iron iron alloys

thermosets

HOW / AS / LIKE HOW

• CÓMO (indirect question) (e.g. He told me how to do it)• LO + ADJ/ADV (e.g. Tell me how fast the car runs)

LIKE• Adjective = IGUAL o SEMEJANTE (opposite :“unlike”)

(e.g. Like poles repel and unlike poles attract)• COMO, PARECIDO A, IGUAL (QUE)

(e.g. A computer is like a typewriter)• COMO POR EJEMPLO (e.g.)

(e.g. Some metals, like steel or brass, are alloys)Expressions

• TO BE LIKE (e.g. What is it like?)• TO LOOK LIKE = SER PARECIDO A

(e.g. This object looks like a square box)

AS• Comparative : “as ... as”

(e.g. Thermoplastics can be heated as many times as required)

• In co-relation with SAME : “the same as”(e.g. Rubber has the same properties as plastics)

• EN CALIDAD DE / COMO(e.g. Oil is used as a fuel)

• COMO + independent clause(e.g. As I was saying, magnetic fields cannot be seen)

• A MEDIDA QUE(e.g. Steel becomes hard as it cools down)

• PUESTO QUE(e.g. Copper is widely used in wires as it is ductile and malleable)

Expressions• AS IF / AS THOUGH = COMO SI (+ subjunctive)• SO AS TO = CON OBJETO DE, PARA (+ infinitive)• AS FAR AS = EN CUANTO A , CON RESPECTO A

EXERCISE1. AS expected, the lecture began 2 hours late.2. I am going to explain HOW electrolysis can be used AS a process to coat

objects with thin films of metals LIKE/SUCH AS chromium or gold.3. Electroplating is LIKE painting an object but covering it with a metal.4. We can observe HOW the needle moves AS we place the compass near

a coil.5. A piece of iron can be used AS a magnet when it is magnetized.6. Thermosets break down AS their temperature rises.7. Some metals, LIKE/SUCH AS aluminium and copper, are pure metals.8. I have never used a device LIKE this one before.9. Semiconductors act AS conductors under certain conditions but AS

insulators under others. 10. Electrons are attracted by positively charged particles AS they have a

negative electric charge.11. The boiler of a power plant works LIKE a big kettle.12. I would like to work AS an engineer for your company.13. We can mention steel AS an example of an alloy.14. A piece of iron is placed inside the coil SO AS TO increase the magnetic

properties of the metal

GRAMMAR REVISION There are MANY (muchos) types of STEEL (acero) DEPENDING

ON/ON THE BASIS OF/ACCORDING TO (según) the materials added to it.

For example, steel that contains VERY LITTLE (muy poco) CARBON (carbono) is known AS (como) low carbon steel, and it is very malleable.

HOWEVER (Sin embargo) steel with a higher carbon content becomes LESS (menos) malleable, AS (ya que) carbon makes it harder and THEREFORE (por lo tanto) more difficult TO MOULD/SHAPE (de moldear), but ON THE OTHER HAND (por otra parte) it can resist higher loads.

Other types of STEEL (acero) include some other materials, LIKE/SUCH AS (como) chromium to make STAINLESS STEEL (acero inoxidable).

THUS (Así pues), we can classify steel INTO (en) different groups ACCORDING TO (según) the properties that we require and HOW (cómo) the steel is manufactured.

CONNECTORS1. Copper is a good conductor, THEREFORE/THUS it is used

in wires.2. Cast iron is not used to withstand impact loads

BECAUSE/AS/SINCE it is a brittle material.3. Titanium is used for aircraft frames BECAUSE/AS/SINCE it

is light and strong.4. Chromium resists corrosion THEREFORE it is added to

steels to make them rust proof.5. Aluminium and iron are pure metals WHEREAS/WHILE

bronze and steel are alloys6. Stainless steels have a high strength. HOWEVER, they are

expensive and difficult to machine.7. Tin is used to coat other materials to protect them

BECAUSE/AS/SINCE it resists corrosion8. Tin is expensive; THUS/THEREFORE the coats of tin are

very thin.9. Nickel & chromium improve the properties of metals;

THEREFORE /AS A RESULT they are added to steel10. Alloys, i.e. / THAT IS mixtures of materials,….

ESSAY 1 (Units 1-2)In about 150 words write different CLASSIFICATIONS for the

materials of the book (p30) and DESCRIBE some of them. USE STRUCTURES OF UNITS 1 (p 13) & 2 (p 27)

INCLUDE and UNDERLINE:

- BASIS OF CLASSIFICATION (p 27)

- THE EXPRESSIONS AS, HOW & LIKE (p28)- AT LEAST 3 CONNECTORS - STRUCTURES of DESCRIPTION (p13) & CLASSIFICATION- 5 ADJECTIVES FORMED WITH A SUFFIX (p 17)

DEADLINE: 13th MARCH (essays will only be accepted within given timelines)