p2 - energy transfer by heating Flashcards
define thermal conductors
allow thermal energy to move through them easily
give examples of good conductors
metals
define thermal insulators
materials that do not allow thermal energy to move through them easily
give examples of thermal insulators
fibreglass, wool (because they trap air)
give three factors that the rate of thermal energy transfer relies on
- temperature across the metal
- thickness of the metal
- thermal conductivity of the metal
give two factors that reduce the rate of thermal energy transfer
- have as low a thermal conductivity as possible
- be as thick as possible
what happens when you heat a substance?
you transfer energy to it which increases its temperature
define ‘specific heat capacity’
amount of energy required to raise the temperature of 1kg of the substance by 1 degree celsius
the greater the specific heat capacity of a substance…
the more energy you would need to supply the substance in order to increase temperature by 1 degree celsius
what would a greater mass mean in terms of shc?
requires more energy to increase temp by 1 degree celsius
give equation to change temp by a set amount
change in energy (J) = mass (kg) x c, specific heat capacity (J/kg degrees celsius) x temperature change in degrees celsius
what does fibreglass loft insulation do?
reduces the rate of energy transfer through the roof
what does cavity wall insulation do?
reduces the rate of energy transfer through the outer walls
what does aluminium foil do?
behind radiators and reflects infrared radiation back into the room
what does double glazing do?
reduces rate of energy transfer through the windows
