Materials - Which is better: Man made or Natural?

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Materials: Which is better: Man made or Natural?

Students like myself need to know what materials are available, how they behave in use and how they can be worked or processed during manufacture and construction.  Having a good understanding of these will help me to select suitable materials for my products.

In choosing materials for a particular project, I will need to consider their physical and working properties, so that I am able to decide which material is best and which method of processing is required in order to turn raw materials into finished products.

I have to use a procedure called product analysis.  This involves analysing and existing product in order to identify the materials that have been used, the properties that make them suitable for the task for which they have been designed as well as an awareness of the processes used in their manufacture, construction and assembly.  All man-made materials are derived from one or several naturally found materials.

History of materials

Early human history is divided into eras named after the materials that were predominantly used at the time.  The Stone Age, Copper age, Bronze Age and Iron Age suggest how important these materials were in the development of early technology.

Early humans could only utilize the materials that they found to hand.  Stone, reeds, clay, wood, animal hides, hair and bone enabled them to survive in otherwise inhospitable conditions.  During these earliest periods organic materials were by far the most important and useful.  Human resources were greatly enhanced by the discovery that mixing and heating materials, often change their characteristics.  Ceramics (the earliest inorganic material to be used and worked) are good examples.  A pliable clay can be moulded into the required shape and heated to create a much harder and tougher material, because the micro-structure of the clay changes during the firing process.

From about 8000BC humans in the middle-east, crafted locally found gold and copper to make decorative items.  By about 4000BC they had learned how to smelt copper from ore.  Around 2000BC it was found that another soft metal, tin, could be added to copper to produce an alloy which possessed some of the features of both parent metals.  This alloy was an attractive gold coloured metal, which was much harder than either copper or tin.  This led to the beginning of the Bronze Age.

The extraction of iron from haematite (iron ore) began about 1200BC.  In its pure form iron is inferior to bronze in almost every way, but people found that by heating iron and charcoal and hammering it into shape produced a much tougher metal, steel.  They also found that by plunging heated metal into cold water (quenching) they were able to produce a very hard, but brittle steel (hardening).  They soon learned that these properties could be modified by reheating and cooling more slowly (tempering) so that most of the initial hardness was retained whilst at the same time making it much tougher and less brittle.  This of course would not have been possible without natural materials like wood and plants, to set on fire to melt the metals.

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Although naturally occurring polymers such as bitumen shellac and rosin have been used since 2000BC it was not until 1862 that the first manufactured plastic called parkesine was developed.  In 1906 a chemist called Baekeland produced the first synthetic polymer Bakelite.  Since then many new plastics with different colours and properties have been developed.

In the last 100 years our knowledge and understanding of materials has grown considerably.  Today our use of traditional materials are constantly being improved and new materials are being synthesised from natural and man-made materials.  We now have glass that is stronger than steel, ceramics that ...

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