(Topic 10) Using Resources (CGP Book) Flashcards
What are ceramics?
Non-metal solids with high melting points
How are ceramics made using clay?
Clay is a soft material when dug up out of the ground
So can be moulded into different shapes
When fired at high temperatures, it hardens to form a clay ceramic
How can Glass be used to make ceramics?
Glass is generally transparent, can be moulded when hot and can be brittle when thin
Most glass made is soda lime glass
What is soda lime glass?
Made by heating a mixture of limestone, sand, and sodium carbonate until it melts
It is then left to cool
What is borosilicate glass?
Higher melting point than soda lime glass
Made using a mixture of sand and boron trioxide
What are composites?
One material embedded in another
Fibres or fragments of a material are surrounded by a matrix acting as a binder
What are examples of composites?
Fibreglass
Carbon fibre
Concrete
Wood
What is fibreglass?
Consists of fibres of glass embedded in a matrix made of polymer
Has a low density, but is very strong
What is carbon fibre?
Have a polymer matrix
Reinforcement is either made from long chains of carbon atoms bonded together from carbon nano tubes
These composites are very strong and light
What is concrete?
Made from aggregate, which is a mixture of sand and gravel, embedded in cement
Very strong
What is wood?
A natural composite of cellulose fibres held together by an organic polymer matrix
What is low density polythene made from?
Eating at a moderate temperature under a high-pressure
It is flexible
What is high density polythene made from?
Ethan, but at a lower temperature and pressure with a catalyst
More rigid
What are thermo softening polymers?
Contain individual poly machines and twined together with weak forces between the chains
Can be melted and remoulded
What are thermosetting polymers?
Contain monomers that can form cross-links between the polymer chains, holding the chains together in a solid structure
Don’t soften when heated
Strong, hard and rigid
Properties of polymers
Insulators
Flexible
Easily moulded
Properties of metals?
Malleable
Good conductors
Ductile
Shiny
Stiff
Properties of ceramics?
Insulators
Brittle
Stiff
What are commonly used alloys?
Bronze - copper + tin
Brass - copper + zinc
Gold alloys
Aluminium alloys