T10: using resources Flashcards
What do humans use the Earth’s resources for?
Humans use the Earth’s resources to provide warmth, shelter, food and transport.
What are ceramics?
Non metal solids with high melting points that aren’t made from carbon based compounds.
What are some examples of ceramics?
clay and glass
What is clay and how does it make a clay ceramic?
- clay is a soft material when it’s dug up out of the ground so can be moulded into different shapes.
- When it’s fired at high temperatures, it hardens to form a clay ceramic.
Why is clay ideal for making pottery and bricks?
its ability to be moulded when wet and then hardens makes clay ideal for making pottery and bricks.
What is glass like?
Glass is generally transparent, can be moulded when hot and can be brittle when thin.
What are the 2 types of glass?
soda lime glass and borosilicate glass.
What type of glass is most glass?
soda lime glass
How is soda lime glass made?
Made by heating a mixture of limestone, sand and sodium carbonate (soda) until it melts.
When the mixture cools it comes out as glass.
What is the differences between soda lime glass and borosilicate glass?
- borosilicate glass has a higher melting point.
- both made in the same way but borosilicate glass uses a mixture of sand and boron trioxide.
What are composites and how are they made?
- made of one material embedded in another.
- fibres or fragments of a material (known as the reinforcement) are surrounded by a matrix acting as a binder.
What do the properties of a composite depend on?
the properties of the material it is made of
What is fibreglass made of and what is its properties + uses?
- consists of fibres of glass embedded in a matrix made of polymer (plastic).
- it has a low density (like plastic) but it is very strong (like glass).
- used for skis, boats and surfboards
What is carbon fibre made of and what is its properties + uses?
- have a polymer matrix
- the reinforcement is either made from long chains or carbon atoms bonded together (carbon fibres) or from carbon nanotubes.
- these composites are very strong and light so used in aerospace and sports car manufacturing.
What is concrete made of and what is its properties + uses?
-made from aggregate (mixture of sand and gravel) embedded in cement.
- very strong.
- ideal for use as a building material e.g. in skate parks.
What is wood?
Wood is a natural composite of cellulose fibres held together by an organic polymer matrix.
What things influence the properties of a polymer?
- how it’s made
- what it’s made from
What does the properties of poly(ethene) depend on?
- the catalyst that was used
- the reaction conditions (the temperature and pressure) that it was made under.
How is low density (LD) poly(ethene) made and what is its properties/uses?
- made from ethene at a moderate temperature under a high pressure
- flexible
- used for bags and bottles
How is high density (HD) poly(ethene) made and what is its properties/uses?
- made from ethene but a a lower temperature and pressure with a catalyst.
- more rigid
- used for water tanks and drainpipes
What determines the type of bonds that form between the polymer chains?
The monomers that a polymer is made from
What determines the properties of the polymer?
These weak bonds between the different molecules chains
What do thermosoftening polymers contain?
individual polymer chains entwined together with weak forces between the chains.
You can melt these plastics and remould them.
What do thermosetting polymers contain?
monomers that can form cross links between the polymer chains, holding the chains together in a solid structure.
What is the difference between thermosetting and thermosoftening polymers?
- Unlike thermosoftening polymers, thermosetting polymers don’t soften when they’re heated.
- thermosetting polymers are strong, hard and rigid.
What are the properties of ceramics?
(including glass and clay such as porcelain and bricks)
- they are insulators of heat + electricity
- brittle
- stiff
What are the properties of polymers?
- insulators of heat + electricity
- flexible
- are easily moulded
What are polymers used in?
clothing and insulators in electrical items
Why are there many different uses of composites?
their properties depend on the matrix/binder and the reinforcement used to make them.
What are the properties of metals?
- malleable
- shiny
- ductile
- good conductors of heat + electricity
- stiff
What are the uses of metals?
cutlery, car bodywork and in electrical wires.
Why do pure metals not always have the properties needed?
Pure metals’ regular structure makes them too soft for use in every day life.
How are alloys made and why are alloys more useful than pure metals?
- made by adding another element to the metal.
- this disrupts the structure of the metals, making alloys harder than pure metals.
How are alloys of irons (steels) made?
By adding small amount of carbon and sometimes other metals to iron.
What are the 3 different types of steels and what are their properties + uses?
1) Low carbon steel (0.1-0.3% carbon)
properties: easily shaped
use: car bodies
2) High carbon steel (0.22-2.5% carbon)
properties: inflexible, brittle, very strong
use: bridges
3) stainless steel (chromium added + sometimes nickel)
properties: corrosion resistant, hard
use: cutlery
What is bronze made
