(a) Make a labelled diagram of a candle flame:
(b) What makes the middle zone of a candle flame luminous (or light-giving) ?
(a) Make a labelled diagram of a candle flame:
(b) What makes the middle zone of a candle flame luminous (or light-giving) ?
Outer Zone: This zone is blue in colour. It is the hottest part of the flame because complete combustion takes place in this zone.
Middle Zone: This zone is yellow and orange in colour. This zone is moderately hot because partial combustion takes place in this zone.
Inner Zone: This zone is dark in colour. This is the coolest part of the flame because no combustion takes place in this zone. 
The middle zone of a flame is yellow and it is bright and luminous. it is an oxygen-depleted zone.
Reason: The fuel vapours burn partially in the middle zone because there is not enough oxygen air of burning in this zone.
The partial burning of fuel in the middle zone produces carbon particles. It indicates the deposition of unburnt carbon particles present in the luminous zone of the flame. These carbon particles then leave the flame as smoke and soot. It has a moderate temperature.
Outer Zone: This zone is blue in colour. It is the hottest part of the flame because complete combustion takes place in this zone.
Middle Zone: This zone is yellow and orange in colour. This zone is moderately hot because partial combustion takes place in this zone.
The middle zone of a flame is yellow and it is bright and luminous. it is an oxygen-depleted zone.
Reason: The fuel vapours burn partially in the middle zone because there is not enough oxygen air of burning in this zone.
The partial burning of fuel in the middle zone produces carbon particles. It indicates the deposition of unburnt carbon particles present in the luminous zone of the flame. These carbon particles then leave the flame as smoke and soot. It has a moderate temperature.
