DIYbanter - View Single Post - Conduction, Radiation, and Convection? Is that all there is?

Keith Williams

In article ,
says...
In high school physics, the three methods of heat dispersal were
presented as conduction, radiation, and convection?

Is that all there is? Is diffusion a fourth or is it subsumed by
convection?

I'd say conduction, rather then convection. Heat is transfered by
the molecules bouncing off each other = conduction.

I could be wrong but:
Conduction seems to be limited to within a solid, or from the surface
of a solid to that part of a liquid or gas in contact with the solid.

No, liquids and gases also conduct. Convection may be dominant
though.

ICBWB:
Convection seems to be limited to liquids and gases.

Sure, something's gotta move for convection. Solids don't move too
well. ;-)

And ICBWB: radiation seems to be limited to from a solid or maybe a
liquid through a gas to another solid or maybe a liquid.

No, radiation occurs with all substances but at moderate
temperatures can be dwarfed by conduction and convection. We see
Jupiter (a "gas giant") by radiation, for instance.

As to convection, it was always described and seems to be limited to
broad currents, such as hot air rising and cold air sinking, but is
that all that happens? In, say, a room with moderate cooling in the
summer or moderate heating in the winter, while in general the hot air
rises, doesn't the random motion of some of the hot air cause it to go
downward and to mix with the cooler air below it? Is this radiation?

Some by radiation, some by conduction, mostly convection though.

Is it still convection? Or is it diffusion and for reasons of
definition, not one of the other three?

Diffusion normally relates to different gases/liquids. If they're
the same I'm not sure how you track the molecules. They'll swap
heat by bumping into each other (conduction).

--
Keith