Heating and cooling revision notes for science

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Heat can be transferred from place to place by conduction, convection and radiation.   Dark matt surfaces are better at absorbing heat energy than light shiny surfaces, however light, shiny surfaces are good reflectors of infra-red radiation.  Heat energy can be lost from homes in many different ways and there are ways of reducing these heat losses.

Infra-red radiation:-

  • All objects emit and absorb thermal radiation (infra-red radiation). The hotter an object is, the more infra-red radiation it emits.
  • Infra-red radiation is a type of electromagnetic radiation, which involves waves rather than particles.
  • Unlike conduction and convection, radiation can pass through the vacuum of space. This is why we can still feel the heat of the Sun, even though its 150 million km away from the Earth.

Kinetic theory:-

The kinetic particle theory explains the properties of the different starts of matter.

  • The particles in solids, liquids and gases have different amounts of energy.
  • They are arranged differently and move in different ways.

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Conduction:-

Heat energy can move through a substance by conduction.

  • Metals are good conductors of heat but non-metals and gases are usually poor conductors of heat.
  • Poor conductors of heat are called insulators.
  • Heat energy is conducted from the hot end of an object to the cold end.

Heat conduction in metals:-

  1. The electrons in piece of metal can leave their atoms and move about in the metal as free electrons.
  2. The parts of the metal ...

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