Page 93 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

You may be able to identify some uses of metals when you
observe the picture given at the beginning. Don't you think
that these uses are possible due to certain special properties
of metals?
How do you know whether an object is made of metal?

• By testing its hardness
• By heating
•

General characteristics of metals

Fig. 7.1 (a) Which of the characteristics of metals are you familiar with?
The table given below lists some metals. Complete the table
by listing their characteristics as well as the objects which
make use of those characteristics.
Metal Property Objects

Gold Lustrous, Resistant to corrosion Ornaments
Copper
Fig. 7.1 (b) Iron

Aluminium
Table 7.1
With a hammer, beat forcefully on an aluminium wire kept
on a hard surface. What do you see?

Haven't you noticed aluminium foils used to wrap
chocolates and sweets? Which property of the metal is
utilised here?

Fig. 7.1 (c) Metals can be beaten into thin sheets by hammering.
This property is known as malleability.

Gold is the most malleable metal.
Gold is the most Try to find more instances where malleability of metals is
malleable metal employed.
One gram of gold can be
beaten into sheets with an
Ductility is another useful property of metals.
area of about 6.7 square
feet and can be drawn into Metals can be drawn into thin fine wires. This property is
a wire of about 2 km in known as ductility.
length.

92 Basic Science VIII