conduction and radiation Flashcards
which is a conductor and which is an insulator out of metals + non-metals?
Metals are the best conductors with a high energy transfer and non-metals are insulators with a low energy transfer.
what is convection? what happens when particles are cold/hot?
the movement of heat in fluids. The particles in the fluid become less dense when hot, rise and float. When cold the particles become denser and sink.
how do hot objects radiate heat?
in the form of waves. There is no need for particles.
why are houses insulated?
to prevent energy loss and save energy resources and money.
what does double glazing prevent and why?
heat loss because they have a trapped layer of gas so both conduction and convection cycles are disrupted.
what is insulating panels made of + why?
of a foam and coated with foil, this reduces radiation, conduction and convection.
what do all objects absorb and emit?
radiation, the hotter the more it gives out.
what does the earth’s temperature depend on?
on radiation from the sun
what happens when increasing the number of layers of insulation?
decreases thermal transfer so the
temperature loss is less.
why are materials with trapped layers of air good insulators?
because heat does not transfer well between solids and gases.
