AQA ------ Materials and their working properties Flashcards
- Papers and Boards - Timbers - Metals and Alloys - Polymers
What are papers and boards made from?
Natural fibres (cellulose) usually from wood.
What is paper weighed in?
GSM (Grams per Square Metre)
When would their be a need for bleached pulp?
For the use of high quality ‘bright’ paper
What are the 3 stages of paper and board production?
1 - Pulping
2 - Sizing
3 - Calendering (Draining +Rolling)
How is pulp created?
- Natural cellulose fibres are mixed with water.
- The mixture is cooked which produces a fibrous liquid known as pulp.
- It is spread onto a mesh conveyor which gets rid of excess water.
What is a Micron?
A unit to measure board thickness, 1000 microns is equal to 1 mm thickness.
What are the 2 categories of natural wood?
- Hardwood
- Softwood
What is ‘felling’ a tree?
A tree is ‘felled’ when it is cut down.
Which trees do Hardwood come from?
Coniferous trees
Which trees do Softwood come from?
Deciduous trees
Why are softwoods good for paper production?
- Softwood trees grow faster than Hardwood.
- Coniferous trees are usually evergreen.
- Hardwood is more expensive.
What are the 4 working properties?
- Strength
- Toughness
- Elasticity
- Hadness
What are manufactured boards?
usually sheets of processed natural timber waste or sawdust combined with adhesives
What are manufactured boards?
usually sheets of processed natural timber waste or sawdust combined with adhesives
What is Ore?
A type of rock which contains a pure metal in small quantities.
How is metal extracted from ore?
- (Ore is obtained from mining)
- The metal is then extracted using a large furnace
- The heat of the furnace separates the metal from the ore and it is drown off as a molten liquid.
What are the 3 categories metals are put into?
- Ferrous
- Non-Ferrous
- Alloys
How is metal extracted from oxides?
Heated with carbon to extract the metals.
How is metal extracted from ore?
- (Ore is obtained from mining)
- The metal is then extracted using a large furnace
- The heat of the furnace separates the metal from the ore and it is drown off as a molten liquid.
What are the properties of a ductile metal?
+ Will stretch without being damaged.
+ Can be stretched or drawn out into long wires.