Materials

• ceramics


  made out of clay, sand and feldspar that has been dug out of the ground and heated in a kiln oven at high temperatures (700-2000 degrees)
• properties of ceramics:

  • very high melting and boiling points
  • easily shaped (malleable)
  • strong and hard
  • brittle (in nature)
• lattice structure


  billions of atoms joined together by strong bonds in a regular pattern
• ceramic material


  non-metal substance that is unaffected by heat
• Why do quartz need a high melting point and what is it used for?

  There are a lot of strong bonds holding the atoms together. A lot of energy is needed to break these bonds and melt the solids. This is useful for drilling and brake discs.
• Why do quartz need to be hard and what is it used for?

  The bonds are strong and cannot slide over each other, meaning the structure is rigid. This is useful for sandblasting and sanding.
• Quartz is made of silicone and oxygen and strong bonds that are holding the atoms together.
• Natural polymers:

  • Rubber
  • DNA
  • Proteins
  • Starch
  • Cellulose
• Synthetic polymers are made from raw materials obtained from crude oil.
• Exothermic reactions


  transfers energy to the surroundings
• endothermic reactions


  absorbs energy from the surroundings to make them cooler
• Polymerisation is an exothermic reaction because it transfers

  energy to the surroundings, which makes them warmer.
• polymer


  a very long molecule, made up of many small repeating molecules known as monomers that are joined together
• During polymerisation, the monomers (small molecules) join with the polymers (long molecules).
• Rubber is described as an elastic because it returns to its original shape after being stretched.
• Weak intermolecular forces let the polymer chains slide past each other.
• What happens to the polymer chains if we heat the rubber?

  They get weaker and the rubber bands get longer because the molecules can easily slide over each other.
• composites

  materials made by combining two or more different types of material to combine their useful properties into one