Energy Flashcards
Testing rods of different materials as conductors:
Testing rods of different materials as conductors:
Rods need to be the same width and length
They are coated with thin wax on one end
The uncoated ends are heated together
what happens to the amount of energy transfered depending on the thermal conductivity of a material
The greater the thermal conductivity of a material, the more energy per second it transfers by conduction
The energy transfer through a layer of an insulator depends on:
the temperature difference across a material
thickness
the thermal conductivity of an insulator
if you want to reduce the energy transfer:
the material should have low thermal conductivity
high level of thickness
What spectrum is infrared radiation part of ?
Electromagnetic spectrum
What objects give off infrared radiation?
all objects
What does a body at constant temperature mean in term of infrared radiation?
a body at constant temperature is absorbing infrared radiation at the same rate that it’s emitting it
what do white materials do in terms of
absorb less, emit less
what do black materials do in terms of
absorb more, emit more
When heated up, a temperature increase depends on
-The mass of a substance
-What the substance is
-The amount of energy supplied to it
Ways to reduce heat loss:
Cavity wall insulation reduces rate of thermal energy through outer walls of house
Loft insulation = fibreglass reduces rate of energy transfer through the roof, and put layers of insulation in the roof
Aluminium foil between the radiator and the wall - radiation reflects off the wall into the room
double-glazed windows - the thicker the glass the lower its thermal conductivity. vacuum prevents energy transfer by convection
What is convection?
Energy trans
hot to cold
how do solar panels work?
absorb and retain infrared radiation
