|Which objects absorb and emit infrared radiation?
|All objects emit and absorb infrared radiation
|what makes an object radiate more infrared radiation?
|How hot it is, the hotter the object the more infrared radiation it radiates
|What type of surface is perfect for emitting and absorbing infrared radiation?
|Dark, matt surfaces are good at absorbing and emitting infrared radiation.
|what makes a bad surface for emitting and absorbing infrared radiation?
|Light, shiny surfaces are bad at emitting and absorbing infrared radiation.
|What sort of surface would be good at reflecting infrared radiation?
|Light, shiny surfaces
|What does a fluid do when heated?
|Expands, becomes less dense, rises and causes circulation (convection)
|Infrared radiation is transfer of energy by what type of wave?
|What are all materials made out of?
|What are the best conductors of energy?
|What materials are the best insulators?
|Wool and fibreglass
|How does conduction take place?
|free electrons transfer energy inside metals
|Why are non metals not good at conducting?
|They don't have free electrons
|What is convection?
|The circulation of a fluid (liquid or gas) caused by heating it
|What is evaporation?
|When a liquid turns into a gas
|What is condensation?
|When a gas tuns into a liquid
|How does evaporation cause cooling?
|The faster moving-molecules escape from the liquid
|How can evaporation be increased?
|-Increase the surface area of the liquid -Increase the temperature of the liquid -Create a draught of air across the liquid's surface
|How can condensation on a surface be increased?
|-Increase the area of the surface -Reduce the temperature of the surface
|What does the rate of energy transfer to or from an object depend on?
|-The size, shape and type of material of the object -The materials the object is in contact with -The temperature difference between the object and its surroundings
|How will the mass of an object change how quickly the temperature changes when heated?
|The greater the mass, the slower the temperature increases.
|What does the rate of a substance's temperature change depend on when it is heated?
|-The energy supplied to it -Its mass -Its specific heat capacity
|What is specific heat capacity?
|The energy required to raise 1kg of a substance by 1 degree Celsius
|How do you work out specific heat capacity?
|c= E ------- m x (theta) E=Energy transferred (J) m=Mass (kg) c= Specific head capacity (j/kg oC) theta=temperature change (oC)
|How can energy transfer be reduced in our homes?
|-Loft insulation -Cavity wall insulation -Double Glazing -Draught excluders -Aluminium foil behind radiators
|What does a U-Value tell us?
|How much energy per second travels through a material.
|What does a low U-Value mean?
|The material is a good insulator
|What does a high U-Value mean?
|The material is bad at insulating