and explain why they move in this way.
The picture below shows a radiator heating a room in a house.
gcsescience.com 8 gcsescience.com
Heat - Convection (continued).
You may be asked to draw the
direction of convection
currents
and explain why they move in this
way.
The picture below shows a radiator
heating a room in a
house.
The hot
radiator transfers heat to
the nearby air
when air molecules collide with the radiator surface.
The air is also heated by infra-red radiation.
The hot air near to the
radiator expands and increases in volume.
The density of
the hot air
decreases and it starts to rise
upwards.
The colder air above it gets pushed
along to the right
and then circulates as shown by the
arrows.
The arrows show the convection currents.
As the hot air moves around
the room,
it loses its heat by collision
with the walls, ceiling
and the objects in the room.
Finally the colder air circulates near to the radiator where it is heated
and the whole process repeats
itself.
The efficiency of convection can be improved
by placing shiny metal
foil behind the
radiator.
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Copyright © 2008 Dr. Colin France. All Rights Reserved.