Page 1 - Lesson Notes

SAI International School

Class – VIII

Subject – Chemistry

Topic – SYNTHETIC FIBRES AND PLASTICS

Sub-Topic – Plastics and Environment

LESSON NOTES

PROPERTIES and USES OF PLASTICS:

Plastics have many properties which make them the first choice of material for a wide variety of

usage in our daily life.

 Plastic is chemically unreactive:

 Plastics do not react with air and water, which makes it corrosion-resistant.
 Plastics are often not affected by various chemicals, like, acids and bases.
 Since plastics are unreactive and corrosion-resistant, the plastic containers
are used to store various kinds of materials, including many chemicals.
 Plastics are poor conductor of heat and electricity:
 As plastics do not conduct heat and electricity, they can be used as
‘Insulators’.
 Plastics being poor conductor of heat, the handles of cooking utensils (frying
pans, pressure cookers) are made of plastic, so that we can hold the cooking
utensil safely while cooking.
 Plastics being poor conductors of electricity, the electric wires have a plastic
covering as insulation, to protect us from electric current passing through
them.
 The handles of screw drivers, electric switches, plugs and sockets, all have a
plastic covering.
 Plastics can be moulded into different shapes:
 They are used to make a large variety of articles having different shapes and
sizes.
 E.g., buckets, mugs, furniture chairs and tables, bags, slippers, toys, combs,
toothbrushes, etc.
 Plastics are cheap and easily made:
 Plastics are quite cheaper than metals and can be made much more easily
than metals.
 Due to this property, plastics are now used for making many of the household
and industrial articles which were earlier made from metals. E.g., Buckets
used in our homes.

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