EFL Tech - France a Site for Teachers of English ( as a Foreign Language) for  Engineering

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A - Introduction
Classifying is a usual activity in technology since facts are collected and arranged in groups or categories having some common features. For instance, when talking about road going vehicles, we can divide them into cars, lorries, motorbikes and heavy-duty vehicles. Cars can be further classified  into family cars, sports cars, etc.

Classifying can be made
a- from general to specific ( as above);
b- from specific to general ( coupes, roadsters and cabriolets are examples of sports cars).

B - Sentence patterns

1 -  Words often used to specify classification

to classify
to divide
to categorize
to group
types
categories
groups
classes
kinds
examples
species
components

2 - Look at the following graph  (Cards -  Document 1)

3 - From general to specific
Chips cards can be ( may be / are ) classified / divided / categorised into two groups / classes / categories : memory cards and smart cards.
There are two main types / kinds : classes : categories of chip cards : memory cards and smart cards.
Chip cards include memory cards and smart cards.
 

4 - From specific to general
A memory card can be ( may be / is) classified / categorised as chip cards
Memory cards are examples / types of chip cards.
The memory card is an example / type of chip card.
 

5- Note the possible noun patterns
A memory card  is classified ...
The memory card is classified ...
Ø memory cards are classified ...
 

6 - A classifying sentence is often supported by an example:
There are two main kinds of chip cards: memory cards and smart cards. The phone card is an example of memory card.
 

 C- Exercises

1 - Underline the words and phrases used to classify:
    Magnetism is an effect produced by moving electrons in certain materials. Iron, nickel and cobalt are the three elements which clearly possess   magnetic properties. Various materials with similar properties are known as ferromagnetic: they experience forces acting on them when placed near a magnet. Magnets can be classified into:
            - permanent magnets, which retain their properties permanently;
            - electromagnets, which possess magnetic properties due to the presence of an electric current.
    The materials used to manufacture magnets can be categorised into traditional tungsten and cobalt steel alloys and into  new alloys containing aluminum, nickel ( and cobalt), which have made it possible to reduce the size of permanent magnets. 'Alnico' ( Al, Ni, Co, Fe) is an example of such new alloys used  to manufacture very strong permanent magnets.
 

2 - Order the sentences in the logical order ( remember that the first sentence of a paragraph  is usually a generalisation ( topic sentence), and then underline the words and phrases used to classify:
a. Lenses can be categorised into convex and concave types, depending on the thickness in the middle and at the edges.
b. A lens is a transparent objet ( usually made of glass) bounded by 1 or 2 spherical surfaces.
c. For instance, when the emerging light is divergent, a lens forms a virtual image.
d. Depending  on the distance of the object to the lens and on the type of lens, various types of images can be formed.
e. These images can be divided into real and virtual ones.
 

3 - Write classifying sentences

a- Look at Document 2  ( Electronic devices)

b- Classify from general to specific

-Semi conductors. ( Support by an example. See above B6)
-Transistors.

- Silicon diodes / transistors / thyristors.
- Magnetrons / triodes