Online Shiksha

By Savita S. More

Maharashtra Board Class 8 Man Made Materials

The main ingredients of glass are sand (silicon dioxide), soda, lime, and sometimes small quantities of magnesium oxide.

 

How the plastic is produced?

Plastic is produced through a process called polymerization. It involves the synthesis of organic polymers, which are large molecules made up of repeating units called monomers. The raw materials for plastic production are typically derived from petrochemicals, and the process involves various chemical reactions to form the desired plastic polymer.

 

Distinguish between

a.Manmade material and natural material

Manmade Material Natural Material
Produced in factories or laboratories Found in nature, not significantly altered by human processes
Result of human intervention and processing Formed through natural geological or biological processes
Plastic, synthetic fabrics, metals, ceramics Wood, cotton, leather, stone, minerals
Can be extensively modified and engineered Limited modification without human intervention
Depends on human actions, technology, and industry Independent of human intervention, occurs naturally

b.Thermoplastic and thermosetting plastic

Thermoplastic Thermosetting Plastic
Softens and becomes pliable when heated Sets irreversibly when heated
Can be molded and reshaped multiple times Sets into a rigid form upon initial molding
Can be recycled and reused multiple times Usually cannot be recycled
Polyethylene, PVC, Polypropylene Bakelite, Melamine, Epoxy resin
Packaging, toys, containers, pipes Electric switches, cookware handles, composites
Sensitive to heat, may deform at high temperatures Resistant to high temperatures, retains shape when heated
May be affected by certain chemicals Chemically stable, resistant to many chemicals

 

 

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