CH 3 IR Insulating and others Flashcards
What does a material’s thermal conductivity tell you?
The thermal conductivity of a material is a measure of how quickly energy transfers through it by heating
What materials have a low thermal conductivity?
Thermal insulators
Give 3 factors that affect the rate of thermal energy transfer through a material
-thermal conductivity of a material
-temperature difference
-thickness of material
What 3 factors affect heat loss from a building?
-thickness of walls and roof
-thermal conductivity of walls and roof
-temperature difference between the two sides of the wall/roof
What is the specific heat capacity?
The amount of energy needed to raise the temperature of 1kg of a material by 1*C
What is Infrared radiation?
a type of EM radiation to do with heat
What is the relation between the temperature of an object and its emission of infrared radiation?
the higher the temperature of an object, the more infrared radiation in a given amount of time
What can you tell about an object that absorbs and emits infrared radiation at the same rate?
it is at a constant temperature
Compare the amount of IR emitted and absorbed by an object that is increasing in temperature
more infrared radiation absorbed than emitted
What is a perfect black body?
a theoretical object that absorbs 100% of the radiation that falls on it, and does not reflect or transmit any radiation
Is a black body object the best emitter?
It would be the best possible emitter
Name 3 greenhouse gases
CO2
Methane
Water vapour
What 3 human activities increase the levels of greenhouse gases released?
-deforestation
-burning fossil fuels
-livestock farming
Why do greenhouse gases increase the Earth’s temperature?
The Earth’s surface absorbs and re-emits radiation from the Sun, which greenhouse gases then absorb, they re-emit this radiation back towards the Earth’s surface
