Conduction, convection, radiation, and insulation

• the best conductors are: silver, copper, aluminium, steel, and iron
• conduction happens when particles are hot they vibrate more. This causes them to collide with adjacent particles and transfer thermal energy
• heat energy travels from hotter to colder areas
• when there is a larger temperature difference energy transfers faster
• conduction only happens in solids
• poor conductors are called insulators
• metal is a good conductor whereas plastic is a bad conductor
• metals have a different structure to other solids
• convection happens in liquids and gases
• convection currents are when warmer particles rise to replace colder ones. when they cool they sink and are then replaced themselves.
• convection currents cause heat transfer
• radiation travels through waves meaning it can travel through space
• the earth is warmed by infra-red radiation
• infra-red rays can; travel in a vacuum, travel at the speed of light, be reflected and absorbed, and travel in straight lines.
• matt black surfaces are the best emitter of radiation whereas shiny silver surfaces are the worst emitter of radiation
• radiation travels in straight lines in all directions
• radiation is used by solar panels
• insulation is a material that does not allow charge or heat to pass through it easily
• insulation reflects radiation or decreases conduction/convection
• loft insulation


  stops heat escaping through the roof
• double glazing


  stops heat escaping through closed windows
• electrical insulators do not allow electricity to pass through them
• examples of electrical insulators are plastic wood and rubber