P2: Energy transfer by heating Flashcards
What affects the rate at which heat energy is lost?
Thermal conductivity of the wall (the higher it is, the higher the rate of energy transfer)
Describe the structure of the walls in the home
External brick wall, internal breezeblock wall. Cavity in the middle, containing insulating material to reduce heat loss
Where can thermal energy be lost in the house?
Walls
Windows
Roof
How can the rate of thermal energy transfer from the windows be slowed?
Double glaze the window
How can the rate of thermal energy transfer from the roof be slowed?
Loft insulation
How can the rate of thermal energy transfer from the walls be slowed?
Thicker walls
Insulation
What is the specific heat capacity of a substance?
The amount of energy required to raise the temperature of 1kg of the substance by 1C
What is the formula for specific heat capacity?
Change in thermal energy (J) = mass (kg) * specific heat capacity (J/kgC) * temperature change (C)
Why are metals good thermal conductors?
Their ions are close together, meaning they vibrate quicker when exposed to heat
What is a conductor?
A material that allows heat to be passed through it easily
What is infrared radiation?
Radiation whose wavelengths are longer than those of visible light
What is a perfect black body?
A body which emits and absorbs a lot of radiation
What are the 3 forms of energy transfer?
Conduction
Convection
Radiation
Describe conduction
When heated, atoms in a solid will vibrate faster. Collisions between the atoms will result in the transfer of energy
Describe convection
Occurs when particles with a lot of heat energy take the place of particles with less heat energy
