Properties of material

I. Look at these examples:

A man can easily lift a large roll of

glass wool but not a concrete beam.

Glass wool is light but concrete is

A man can bend a rubber tile but not a concrete tile.

Rubber is flexible but concrete is rigid.

Wood can burn but concrete cannot burn.

Wood is combustible but concrete is non-combustible.

Water vapour can pass through stone but not through bitumen.

Stone is permeable but bitumen is impermeable.

You can see through glass but not through wood.

Glass is transparent but wood is opaque.

Stainless steel can resist corrosion butmild steel cannot.

Stainless steel is corrosion resistant but mild steel is not corrosion resis­tant.

Heat can be easily transferred through copper but not through wood.

Copper is a good conductor of heat but wood is a poor conductor of heat.

Rubber can be stretched or com­pressed and will then return to its original shape but clay cannot.

Rubber is elastic but clay is plastic.

Bitumen can be dented or scratched easily but glass cannot.Bitumenis soft but glass is hard.

Look at these diagrams. Match the letters A-H in the diagrams with the sentences below:

Now complete these sentences with properties:

a) The polythene membrane can prevent moisture from rising into the concrete floor. This means that polythene is _______.

b) The T- shaped aluminium section can resist chemical action, i. e. aluminium is ……..

c) The stone block cannot be lifted without using a crane. This means that stone is ___________.

d) The corrugated iron roof cannot prevent the sun from heating up the house, i. e. iron is ……….

e) Glass wool can help to keep a house warm in the winter and cool in the summer, i. e. glass wool is ………

f) The ceramic tiles on the floor cannot be scratched easily by people walking on them. This means that ceramic tiles are ___

g) Asbestos sheeting can be used to fireproof doors. In other words asbestos is ________ .

h) Black cloth blinds can be used to keep the light out of a room, i.e. cloth is ________ .

II. Make sentences about four other properties of materials from this table:

III. Answer the following questions:

Why is glass used for window panes?

Because glass is … .

Why is glass wool used to keep
the heat in hot-water tanks?
Because glass wool has the
property of.....

Why is some steel covered with athin layer of zinc?
Because zinc is...

Why are some fire doors covered
with asbestos sheets?
Because asbestos is..

Why are some metal sheets
formed into a corrugated shape?
Because the corrugated shape
makes the sheet_ ……

Why is concrete used for the .
columns of a building structure?
Because …..

Lesson 10

Part I

Date: 2015-12-24; view: 3946