p2: energy transfers by heating Flashcards
what does a materials thermal conductivity tell you
how well it conducts heat
which materials have low thermal conductivity
thermal insulators
give 3 factors that determine the rate of thermal energy transfer through a material
thermal conductivity of material
temperature difference
thickness of material
what factors affect the rate of heat loss from a building
thickness of wall and roof
thermal conductivity of walls and roof
the temperature difference between the two sides of the wall/roof
define specific heat capacity
amount of energy needed to raise the temperature of 1kg of a material by 1’C
what is infrared radiation
type of electromagnetic radiation
what is the relationship between the temperature of an object and its emission of infrared radiation
the higher the temperature of an object the more the more infrared radiation emitted in a given time
what can you tell about an object that absorbs and emits infrared radiation at the same time
it is at a constant temperature
compare the amount of infrared radiation emitted and absorbed by an object that is increasing its temperature
more infrared radiation absorbed that emitted
what is a black body
theoretical object that absorbs 100% of the radiation that falls on it and doesn’t reflect or transmit any radiation
name 3 greenhouse gases
water vapor
carbon dioxide
methane
what human activities increase the levels of greenhouse gases released
deforestation
burning fossil fuels
livestock farming
why do greenhouse gases increase the earths temperature
earths surface absorbs and re-emits radiation from the sun, which greenhouse gases them absorb
