Materials And Their Working Properties
Overview
A cold chisel and a spanner are both made of steel, and if you use one as the other you will break something. The chisel is hard enough to cut steel and would shatter if you used it as a lever; the spanner bends before it breaks and would be blunt in a minute if you hit it with a hammer. Same element, same appearance, different material, because a fraction of a per cent of carbon and a few minutes in a furnace changed which properties the steel has.
This is the largest topic in the core technical principles and it is the one every other topic leans on: you cannot select a material, choose a process, apply a finish or justify a prototype without it. You will learn the main categories and types of papers and boards, of natural and manufactured timbers, of metals and alloys, and of polymers, and then the physical properties, which are absorbency, density, fusibility and electrical and thermal conductivity, and the working properties, which are strength, hardness, toughness, malleability, ductility and elasticity. The specification is explicit that the properties are examined in relation to the main categories rather than to each named material, which tells you exactly how deep to go. This is core technical principles content, examined in Section A of Paper 1, and it supplied more specimen questions than any other topic.
Objectives
- Students should have an overview of the main categories and types of papers and boards: papers including:
- bleed proof
- cartridge paper
- grid and layout paper
- tracing paper boards including:
- corrugated card
- duplex board
- foil lined board
- foam core board
- ink jet card
- solid white board.
- Natural and manufactured timbers
- Students should have an overview of the main categories and types of natural and manufactured timbers: hardwoods including:
- ash
- beech
- mahogany
- oak
- balsa softwoods including:
- larch
- pine
- spruce manufactured boards including:
- medium density fibreboard (MDF)
- plywood
- chipboard.
- Metal and alloys
- Students should have an overview of the main categories and types of metals and alloys: ferrous metals including:
- low carbon steel
- cast Iron
- high carbon/tool steel
- stainless steel non-ferrous metals and alloys including:
- aluminium
- copper
- tin
- zinc
- brass
- Polymers
- Students should have an overview of the main categories and types of polymers: thermoplastic including:
- acrylic (PMMA)
- high impact polystyrene (HIPS)
- high density polythene (HDPE)
- polypropylene (PP)
- polyvinyl chloride (PVC)
- polyethylene terephthalate (PET) thermosetting including:
- epoxy resin (ER)
- melamine-formaldehyde (MF)
- phenol formaldehyde (PF)
- polyester resin (PR)
- urea-formaldehyde (UF).
- Material properties
- Students should understand the working and physical properties of the materials listed in Material categories (page 16).
- In relation to the main categories outlined above (not the specific materials identified), students should know and understand physical properties such as:
- absorbency (resistance to moisture)
- density
- fusibility
- electrical and thermal conductivity.
- In relation to the main categories outlined above (not the specific materials identified), students should know and understand working properties such as:
- strength
- hardness
- toughness
- malleability
- ductility
- elasticity.
Mind map
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Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Materials And Their Working Properties. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which one of the following is a hardwood? A. Balsa B. Larch C. Pine D. Spruce Answer: A
- A material that can be permanently shaped by hammering without cracking is described as A. brittle. B. ductile. C. elastic. D. malleable. Answer: D
- Which one of the following is a thermosetting polymer? A. Acrylic B. High density polythene C. Polypropylene D. Urea-formaldehyde Answer: D
- Approximately how much carbon does low carbon steel contain? A. Up to about 0.3 per cent B. About 2 to 4 per cent C. About 10.5 per cent D. About 18 per cent Answer: A
- Which board is made from a polymer foam sandwiched between two card faces? A. Corrugated card B. Duplex board C. Foam core board D. Solid white board Answer: C
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