Heat Flashcards
some examples of thermal conductors are:
silver, iron, gold, aluminium, copper
How do particles move in solids?
they vibrate
How do particles move in liquids and gases?
they move rapidly in different directions
what happens to a solid when it’s melted?
becomes a liquid
What happens to a liquid when it’s boiled?
turns into a gas
what happens when a gas is condensed (condensation)?
becomes a liquid
What happens when a liquid evaporates?
becomes a gas
What happens when expansion occurs?
The space between the particles gets greater
give examples where expansion is needed:
hot air balloons, railway tracks - they expand in heat
Give some examples of thermal insulators;
Glass, rubber, plastic, wood
What can heat transfer take place because of?
Convection
What causes heat transfer?
Infra- red radiation
Why can’t the process of conduction take place in a vacuum?
Because it requires particles to be present
What colours are good and bad absorbers of infra-red radiation?
good - dark, matt surfaces
bad - light, shiny surfaces
What colours are good and bad emitters of of infra-red radiation?
good - black, matt surfaces
bad - light, shiny surfaces
What is conduction the process of?
Where heat is passed on through two neighbouring atoms/ molecules rubbing against each other
What are the 4 different things that are used to stop heat transfer:
double glazing, loft insulation, cavity wall insulation, draught excluders
When does convection by radiation take place (give an example)?
When hot air rises and then cools so it falls to the ground
convection current
When does thermal transfer by radiation take place (give an example)?
The heating of the Earth by the Sun
