Convection and radiation are two different methods for moving thermal energy.
Convection requires a
material that can flow, like a liquid or a gas. Radiation is
transport of energy by light (including invisible forms, such
as infrared light).
They are combined in this section for convenience, and not because
they are in any way related.
This picture shows a gas burner and its shadow on a screen.
The flame gives rise to a plume of hot gases that
rise above the burner.
This disturbs the air and casts a shadow,
which reveals how the moving air carries away the
energy of the flame: an example of energy transfer by convection.
Broiling a fish.
The red glow on the heating element
is the visible part of the emitted light, but there is far more invisible
infrared light being emitted. Energy is transferred as light from the
heating element to the fish: an example of transfer of energy by radiation.
