Using Resources

• ceramics are non-metal solids with high melting points


  some ceramics are made from clay, a soft material that can be moulded into different shapes. it hardens at high temperatures

  its ability to be moulded when wet and then hardened to form a clay ceramic

  glass is also a ceramic, transparent and can be moulded
• borosilicate glass has a higher melting point than soda-lime glass


  it is made using a mixture of sand and boron trioxide
• composites are made of one material embedded in another 


  fibres or fragments of a material are surrounded by a matrix acting as a binder.

  the properties of composites depend on the properties of the material it is made from
• fiberglass


  consists of fibres of glass embedded in a matrix made of polymer. it has a low density but is very strong

  used for things like skis, surfboards, and boats
• carbon fibre


  have a polymer matrix

  reinforcement is made from long chains of carbon atoms bonded together from carbon nanotubes

  composites are very strong and light

  used in aerospace and sports car manufacturing
• concrete 


  made from aggregate (any material made from fragments) embedded in cement. very strong

  use in building material
• wood 


  natural composite of cellulose fibres help together by organic polymer matrix
• polymers can have very different properties


  how it is made and what it is made from can affect its properties
• low density poly(ethene) 


  made from ethene at moderate temperature under a high pressure

  flexible and used for bags and bottles
• high density poly(ethene)


  made from ethene but at a lower temperature and pressure with a catalyst

  more rigid and used for water tanks and drainpipes
• the monomer that a polymer is made from determines the type of bonds that form between the polymer chains


  thermosetting polymers contain monomers that can form cross-links between the polymer chains, holding the chains together in a solid state

  don't soften when heated- strong, hard, rigid

  thermosoftening polymers contain individual polymer chains entwined with weak forces these polymers can be melted and remoulded
• ceramics 


  glass, porcelain, bricks

  insulators of heat and electricity

  brittle and stiff
• polymers 


  insulators of heat and electricity

  can be flexible and easily moulded

  many applications in clothing and insulators in electrical items
• metals


  malleable, good conductors of heat and electricity, ductile, stiff, shiny

  many uses in electrical wires, car bodywork, and cutlery
• alloys


  alloys are made by adding another element to the metal. this disrupts the structure of the metal making it harder
• low carbon steel (0.1-0.3% carbon)


  easily shaped

  used in car bodies
• high carbon steel (0.22-2.5% carbon)

  very hard, inflexible

  blades for cutting tools and bridges
• stainless steel (chromium and nickel added)


  corrosion-resistant

  cutlery, containers for corrosive substances
• bronze 


  copper and tin

  bronze is harder than copper

  used to make medals, decorative ornaments and statues
• brass


  copper and zinc

  more malleable than bronze

  used in situations where lower friction is required such as water taps and door fittings
• gold alloys


  used to make jewellery

  pure gold is very soft

  metals are used to harden the gold

  pure gold is described as 24 carat
• aluminium 


  has a low density which is an important quality in aircraft manufacturing

  pure aluminium is to soft for making aeroplanes so it is alloyed with small amounts of other metals to make it stronger
• corrosion 


  iron corrodes easily- rusts, in order to rust it has to be in contact with both water and oxygen

  iron + oxygen + water = hydrated iron(III) oxide

  corrosion happens on the surface of a material where it is exposed to the air- rust is a soft crumbly solid that flakes off exposing more of the surface that rusts again
• aluminium corrosion


  unlike iron, aluminium objects aren't completely destroyed by corrosion

  aluminium oxide doesn't flake away- it becomes a protective layer that sticks firmly to the aluminium below and stops any further reaction taking place
• ways to prevent rusting

  painting/coating with plastic- ideal for big and small structures alike and can be decorative

  electroplating- uses electrolysis to reduce metal ions onto an iron electrode. used to coat iron with a different metal that won't be corroded away

  oiling/greasing- used when moving parts are involved
• sacrificial method 


  placing a more reactive metal with the iron

  water and oxygen then react with the more reactive metal instead of the iron

  an object can be galvanised by spraying it with a coating of zinc. the zinc layer is firstly protective but if it is scratched, the zinc around the site of the scratch works as a sacrificial metal
• natural resources 


  form without human input

  can be replaced with synthetic products or improved upon by man-made processes.

  agriculture provides conditions where natural resources can be enhanced
• natural resources can run out

  renewable resources reform at a similar rate to their usage

  finite (non-renewable) resources aren't formed quickly enough to be replaced as fast as they are being used- fossil fuels, nuclear fuels
• extracting finite resources has risks

  many modern materials are made from raw finite resources

  people have to balance the social, economic, and environmental risks of extracting finite resources

  mining ores is useful- provides jobs and brings in money

  but is bad for the environment and scars the landscape
• sustainable development 


  approach to development that takes account of the needs of present society while not damaging the lives of future generations

  extracting resources can be unsustainable due to the amount of energy used and waste produced

  if the amount of finite resources used are reduced, the resource will last longer
• copper rich ores supply is limited

  bioleaching

  phytomining
• Bioleaching


  bacteria are used to convert copper compounds in the ore into soluble copper compounds, separating the copper from the ore in the process

  the leachate (the solution produced) contains copper ions, which can be extracted by electrolysis or displacement reactions
• Phytomining


  involves growing plants in the soil that contains copper. the plants can't use or get rid of the copper so it gradually builds up in the leaves

  the plants can be harvested, dried and burned in a furnace. The ash contains soluble copper compounds from which copper can be extracted by electrolysis or displacement reactions
• recycling metals is important

  mining and extracting metals takes a lot of energy

  recycling metals often uses less energy than is needed to mine and extract new metal- this also conserves finite resources

  metals are recycled by melting them and shaping them into the new product- the amount of separation required for recyclable materials can change
• glass can be recycled


  glass bottles can be reused without reshaping

  glass is separated by colour and chemical composition before being recycled- the glass is then crushed and then melted to be reshaped for use in glass such as bottles or jars. could be used for a different purpose as insulating glass wool for wall insulation in homes
• life cycle assessments


  a life cycle assessment takes into account every stage of a product's life to assess the impact it has on the environment.

  -getting raw materials

  -manufacturing and packaging

  -using the product

  -product disposal
• getting raw materials 


  extracting the raw materials needed for a product can damage the local environment

  raw materials often need to be processed to extract the desired materials which needs large amounts of energy
• manufacturing and packaging


  manufacturing products and their packaging can use a lot of energy resources and can also cause a lot of pollution

  there can also be waste products which will need to be disposed of
• using the products 


  the use of a product can damage the environment- fertilisers can leach into streams and rivers causing damage to ecosystems

  how long a product is used and how many uses also is a factor that influences the life cycle
• product disposal


  products are often disposed of in landfill sites- takes up space and and pollutes land and water

  energy is used to transport waste to landfill which causes pollutants to be released into the atmosphere

  products might be incinerated which causes air pollution