Making use of energy

• 3 methods of reducing heat loss in buildings

  double glazing

  loft and wall insulation

  thicker walls
• density

  p = mass / volume
• what is always conserved when a substance undergoes a change of state

  mass
• 3 energy transfer

  conduction

  convection

  radiation
• explain using particle model process of convection

  . when heated, fluids expand, making the particles spread out, and making the fluid less dense

  . less dense fluids rise above cooler more dense fluids

  .these cooler fluids then heat up and rise upwards, creating a convection current
• explain using particle model process of conduction in metals

  . metal consists of positive ions and free electrons

  . as temperature increases, ions gain kinetic energy and vibrate

  . this energy is then passed on via collisions to free electrons

  . these electrons transfer kinetic energy to ions further through metal, increasing temperature