1.8-1.13 Categorisation of types, properties, structure of different materials GapFill

Papers come in different types but they are all measured and classified by  densitygsmsizecost, which is a rough guide to their thickness. One type of paper is described as having a bit of surface texture and being creamy or white in colour, which is useful for drawing on with ink and paints. This type of material is known as  inkjet paperduplex boardcartridge papertracing paper. Timbers are classified as hardwoods, softwoods or manufactured boards.  MahoganyAshPineBalsa is an example of a softwood, whereas  cedarlarchoakpine is an example of a hardwood. Hardwood timber comes from a slow-growing tree. These timbers have fine grains and are physically very  darktoughbrittlevisually appealing in comparison to softwoods. Mild steel is a ferrous metal, which means it contains  tincopperironbrass, which also means that it will rust and develop a reddish surface oxide if left untreated. Non-ferrous metals do not contain iron and are, therefore, not  softmagneticmalleableductile. Polymers are made up of long chains of  monomerscarbonhydrogenPVC and are classified as being either thermoforming or thermosetting polymers.  PVCUrea formaldehydePolypropyleneAcrylic is an example of a thermosetting polymer. Textiles can be synthetic or natural.  PolyesterWoolPolyamideAcrylic is an example of a natural fibre. Fabrics that are made by looping warp and weft yarns together are known as  feltedknittedwovenplain fabrics. All materials have their own specific physical properties. A material that is resistant to abrasive wear and indentation is said to have the property of  hardnesselasticitymalleabilityplasticity, whereas a material that returns to its original shape after a deforming force has been removed is said to have  elasticitytoughnessmalleabilityhardness.