January Weeks 12-14 Flashcards
What are physical properties/ characteristics?
Properties that can be measured or calculated without applying any force to the material
What is density?
the mass, per unit volume of any material. how solid is a material
lead has high density
polystyrene has low density
What is absorbency?
the ability of a material to soak up or draw in heat, light or moisture
cotton is more absorbent than acrylic
What is electrical conductivity?
The measure at which a material can transport electricity
eg. copper is a good conductor of electricity
insulators=plastic/ rubber
What is fusibility?
the ability of a material to be converted from a solid to a fluid state by heat and combined with another material
What is thermal conductivity?
The measure of a material’s ability to transfer heat
Copper is an excellent conductor of heat
List all of the physical properties
- absorbency
- density
- electrical conductivity
- fusibility
- thermal conductivity
What are working properties?
Properties that can only be measured by applying a force (compression, tension etc) to the material and seeing how it responds
What is ductility?
The ability of a material to be stretched or drawn or pulled without breaking
copper is ductile so can be drawn out to make wire
What is elasticity?
the ability to return to its original shape after stretching or compression
lycra used for sportswear to provide freedom of movement
What is hardness?
The ability to withstand impact, wear, abrasion (scratching) and indentation
tungsten is hard, used for knives, drills and saws
What is malleability?
The ability to be bent and shaped without cracking or splitting
gold, copper, silver and lead can all be hammered into shape
What is strength?
the ability to withstand a force such as pressure, compression, tension or shear
may be strong in one force but not the other.
concrete is strong in compression but not tension
What is toughness?
the ability to absorb shock without fracturing
kevlar body armour absorbs impact
How is paper measured in?
weight in grams per square metre (GSM)
common weights = 60-170 gsm
What is layout paper used for?
sketch and design work
same as photocopier/ printer paper
What is tracing paper used for?
copying, overlays and tracing drawings
What is cartridge paper used for?
Sketching, watercolours, ink drawings
What is bleed proof paper used for?
high quality illustrations with colour richness and vibrancy
What is grid paper used for?
Scale drawings, model making, scientific diagrams
What is a natural timber?
wood that comes directly off a tree
Where is hardwood from?
- a deciduous tree, which has leaves
- expensive because it is slow growing
- denser than softwoods
List the hardwoods
ash
beech
balsa
mahogany
oak
What is a softwood?
- wood that is from a coniferous tree
- cheap because it is fast growing
- generally softer
- more prone to rot
- fibers are further apart (absorbs more water)
List the softwoods
pine
spruce
larch
Card and board weight range
200 gsm - 300 gsm
selected by thickness and measured in microns
What is corrugated card used for?
Packaging for impact protection and insulation
degradable and recyclable
What is foil-lined card used for?
takeaway containers
What is duplex used for?
medium quality packaging
used with waxy coating for food and drink containers
What is foam core board used for?
model making and mounting artworks
What is inkjet card used for?
printing photographs and artworks
What is solid white card used for?
greetings cards, quality packaging and book covers
What are manufactured timbers?
Sheets of processed natural timber waste products or veneers (thin pieces of wood) combined with adhesives
What is the standard size and thickness of manufactured boards?
2440mm x 1220mm
thickness: 3mm, 6mm, 9mm etc
What is chipboard like?
- larger particles than MDF
- unattractive
- not water resistant
- always covered with plastic veneer
What is medium density fibreboard (MDF) like?
- made from fine timber dust particles
- more attractive than chipboard but less attractive than plywood & natural timbers
- absorbent
What is plywood like?
- when made with hardwood it can look attractive with a good surface finish
- stable in all directions
Manufactured board advantages
- available in very large sheets (much larger than natural wood planks)
- allows large items to be made from a single sheet (wardrobes)
- less expensive than natural timber
- has uniform thickness
- very “stable”, doesn’t warp/ twist
- has a flat smooth surface, suitable for laminated veneer
- has good sound deafening qualities
Manufactured board disadvantages
- large sheets are heavy and difficult to manoeuvre
- less attractive than natural timber
- contains adhesive resin, have to use dust extraction during sanding/ cutting
What is the source of metal?
metal ore
What is a ferrous metal?
metal that contains iron, does rust (if not painted with a finish) and is magnetic
List some ferrous metals
- cast iron
- low carbon/ mild steel
- high carbon steel
What is a non ferrous metal?
metal that doesn’t contain iron, is in the periodic table
resistant to rust, and is not magnetic
What are non ferrous metals used for?
- non magnetic so used for electronics and wiring
- higher resistance to rust but can corrode or oxidise
- commonly used externally for guttering, pipes and road signs
What is an alloy?
a mixture of at least one pure metal and another element to produce a material with enhanced properties
Are alloys harder than metals?
yes, because of their atoms that are not all the same size and the distorted arrangement of the atoms made it hard for the atoms to slide over each other
Composition of high speed steel (HSS)
- chromium molybdenum
- tungsten vanadium
- cobalt carbon
composition of stainless steel
- low carbon 0.03 - 0.08%
- chromium 10.5 - 26%
composition of brass
- copper 65%
- zinc 35%
What are thermoforming polymers?
also known as thermoplastics and thermoforming plastics
polymers that are once formed into shape can be re-formed again multiple times due to heat and can be recycled
What is the source of plastic?
oil
Properties of polymers in general
- tough
- electrical insulators
- have a good strength to weight ratio
- are available in a wide range of colours
- flexible (thermoplastics)
- brittle (thermosetting plastics)
- suitable for mass production processes
- have a smooth surface so easily cleaned
- food safe
how do you identify thermosetting plastics?
name ends in -hyde or resin
what are thermosetting polymers?
also known as thermosets or thermosetting plastics
polymers that cannot be reformed using heat as they burn instead, difficult to recycle
properties of most textiles
- soft
- comfortable
- good strength to weight ratio
- hardwearing
- thermal insulators
- breathable (allows persperation to escape)
- can be dyed
- available in a wide range of colours
Where is cotton sourced from?
cotton plants
Where is silk sourced from?
silkworm cocoon
where is wool sourced from?
animal fleece
What are natural fibres?
made from plant or animal based fibres and are renewable and biodegradable
What are synthetic fibres
made from chemically produced fibres and are not biodegradable
Where are synthetic fibres sourced from?
oil
What are blended fibres?
combine two or more types of fibre to produce a fabric with enhanced properties
What is woven cloth?
made up of two sets of yarns which are threaded at 90 degrees to each other
warp threads fixed in the loom and run the length of the fabric
weft thread run the width of the fabric
What are non woven fabrics?
fabrics made directly from fibres without being spun into yarns
What are yarns?
a continuous length of interlocking fibres
What is a thread?
yarn made specifically for weaving or sewing
What is knitting
a technique of interlocking yarn loops together to produce a fabric
What are the properties of high speed steel and what is it used for?
- can withstand high temperatures when machining at high speed
- used for cutting tools such as drill bits
What are the properties of stainless steel and what is it used for?
- hard, ductile, rust resistant
- used for cutlery, kitchen equipment
What are the properties of brass and what is it used for?
- malleable and easily cast
- good corrosion resistance
- used for music instruments, statues
List all of the working properties
1) ductility
2) malleabiltiy
3) hardness
4) toughness
5) elasticity
6) strength
