Test- Radiation ( insulation and lubrication) Flashcards
Which surface are better absorbers and emitters of radiation
Matt and dark surfaces
Why does Matt dark surface absorb more-radiation
Because Matt surfaces has lots of cavities. So on light surfaces radiation reflects and travels away
Draw a diagram of radiation on light surfaces
Look in book
Draw a diagram of radiation on dark surfaces
Look in book
Explain what happens with ice cream if it is in a hot area
1 hot to cold
2 it will melt cuz if hot air is around the ice cream it is increasing the ice cream temperature
3 if there was a bigger temperature difference the ice cream would melt quicker
Heat always moves from ….
Hot to cold
What does insulation do
Reduces the rate of the energy transfers by heating
Prevents energy loss through heat
A poor insulated house will
Lose more energy and so it costs more to heat. It also means that more pollution, particularly carbon dioxide, is created in order to heat the house
Air is a bad or good conductor of heat
Bad
What would you fill a wall cavity’s with to trap pockets of air between the walls
With fibre glass of polystyrene
Filling the walls with this it reduces what ?
Heat transfer by conduction. It also stops heat in the gap rising by convection
Insulation is a
Layer that keeps heat in
Without cavity wall insulation, heat can escape through wall by …
…. conduction
If there is an air gap between the walls heat can rise and escape by ….
Convection
Cavity wall insulation uses materials like foam to stop this. This is because the foam traps air and air is a good …
Insulator
