# P1.1 Energy transfer

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• P1.1 Energy transfer
• All objects emit and absorb infrared radiation.
• The hotter an object is the more infrared radiation it radiates in a given time.
• Dark, matt surfaces are good absorbers and good emitters of infrared radiation.
• Light, shiny surfaces are poor absorbers and poor emitters of infrared radiation.
• Light, shiny surfaces are good reflectors of infrared radiation
• P1.1.2 Kinetic Theory
• The use of kinetic theory to explain the different states of matter
• DIAGRAMS
• The particles of solids, liquids and gases have different amounts of energy.
• P1.1.3 Energy Transfer by Heat
• The transfer of energy by conduction, convection, evaporation and condensation involves particles, and how this transfer takes place
• The arrangement and movement of particles determine whether a material is a conductor or an insulator
• The role of free electrons in conduction through a metal.
• The idea of particles moving apart to make a fluid less dense, to explain simple applications of convection
• The factors that affect the rate of evaporation and condensation.
• explain evaporation and the cooling effect this causes using the kinetic theory. Candidates should be able to explain the design of devices in terms of energy transfer, for example, cooling fins.
• The bigger the temperature difference between an object and its surroundings, the faster the rate at which energy is transferred by heating
• P.1.1.4  Heating and Insulating Buildings
• U-values measure how effective a material is as an insulator
• The lower the U-value, the better the material is as an insulator.
• Solar panels may contain water that is heated by radiation from the Sun. This water may then be used to heat buildings or provide domestic hot water.
• The specific heat capacity of a substance is the amount of energy required to change the temperature of one kilogram of the substance by one degree Celsius.
• Energy transferred in joules, J
• Mass in kilograms, kg
• Temperature change in degrees Celsius, °
• c is specific heat capacity in J / kg °C