Physical properties of metals and nonmetals this is a very important topic of science .
At a glance
1 - Metals are hard and shiny. Non metals are soft and dull.
2 - Wires can be made out of metals , but not out of non metals .
3 - Metals are good conducter of heat and electricity. Non metals are not .
You are good at anything.
Think and reflect
Why are ornaments usually made of gold or silver rather than the plastic or wood ?
Activity I
You will need :
A cooking vessel , A pencil lead
Steps :
1 - Take a close look at each one of these . How does each one feel ?
Try tapping them with your finger?
Do they make similar sounds ?
2 - Now use this information to select one of two choices that apply.
Did the cooking vessel sound clunky ? If you didn't know what a clunky sound is , it is the type of ringing sound you get when you hit two metalic vessels together . Clunk !
There is a name for this property of metals . It is called being sonorous .
The cooking vessel is also quite shiny , isn't it ? This is because cooking vessels are made of steel , which is mostly composed of the metal iron . We bet you Knew that .
The name of this property is lustre . Metals are said to be lustrous . Iron is pretty , hard , and sonorous , as are many other metals .
There are just three examples . There are many more such metals . The most popular and valuable ones are gold , silver and platinum which you have probably heard about .
Malleability
Take different materials such as iron, aluminium, copper and silver.
Hit all of these with the help of a hammer.
Metals such as iron, aluminium, copper and silver change their shape on beating.
When these are hit harder, they change into thin sheets.
This property by which metals can be drawn into thin sheets is called malleability.
Most of the metals are malleable such as gold, silver and aluminium.
Gold, silver and aluminium are highly malleable.
Non - metals are not malleable.
They cannot be hammered into thin sheets.
Conductivity
Most of the metals are good conductors of heat and have high melting points.
That is why , they are used for Making vessels.
Silver and coppers are the best conductors of heat while lead and mercury are the poor conductors of heat.
For this reason, utensils are coated with copper.
They are good conductor of electricity.
However, bismuth is a bad conductor of electricity whereas silver and gold are good conductors.
Being expensive, silver and gold are not used for making wires .
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