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Using Materials
By the end of this chapter, you should be able to:
a. know that materials used in everyday life can be classified into natural and synthetic group, and how this affects their use in everyday life
b. understand how the physical properties of polymers determine uses in everyday life such as in building, as fabrics, fabricating utensils used in homes, etc.
c. know about the molecular structures of materials and relate this to their use
d. know that polymers are useful long chain molecules made by both natural and synthetic processes
e. understand how the physical properties of polymers determine uses in everyday life such as in building, as fabrics, fabricating utensils used in homes, etc.
f. know how common materials can pollute environment and which materials can be recycled
g. understand that heating changes the structure and properties of some materials
Competency
You should be able to explore how materials are used and relate these uses to their molecular structures.
Sub-topic
Structure of materials that do not shatter easily
Modelling a polymer
Polymer presentation by S.1 class, watch the video, observe the images and answer the questions.
A ball made from polyethene, ballon and nylon net
A white bolb made from water, glue and powdered detergent
A rope made from sisal
A bangle made from paper and nylon thread
Sisal rope and sisal plant
Nylon Rope
Paper bag made from paper and glue
A rope made from banana fibres
A ball made from polythene and papers
A winnowing basket made from palm leaves
Paper bag and nylon Rope
Plastics
These are man-made (synthetic) materials materials.
They can be molded or shaped while hot into different shapes and harden on cooling to give durable products
They are derived from petroleum.
They have special functions like good insulation etc.
The structure of plastics
Polyethene
Polyethene consists of carbon and hydrogen atoms ie the white balls repesent Hydrogen and the black balls represent Carbon
The monomer of polyethene is ethene
Ethene Structure
Nylon
Nylon
It is used to make clothes, fishing lines, ropes etc
It is very strong and flexible.
The polymer contains some nitrogen and oxygen atoms which attract each other by strong forces that hold the chains together
The structure of Nylon
Melamine
It is hard and rigid and can not be stretched
It is used to make tables, desks, plates, cups etc
The structure of melamine
Common Materials that can affect our enviroment
Plastics eg. polythene bags, sweets and biscuit packaging etc.
Materials that can be recycled
The process of recycling depends on the nature of material.
Paper
metals
glass
plastics
Paper Recycling
Materials made from recycled paper include:
Metal recycling
How do you dispose metals? "scrap"
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To recycle metal it is heated to melting and reshaped.
Glass recycling
Glass is risky when poorly disposed
To recycle, the glass is broken into small pieces and the melted and recast
Plastic recycling
The plastics are collected, sorted and heated then allowed to cool.
End of chapter questions
Activity of integration
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