In this video, 3 different zones of the flame are shown to us:
· Innermost zone
· Middle zone or the luminous zone
· Outermost or the non-luminous zone.
Out of which outermost zone is the zone of complete combustion , rest of the two zones shows incomplete or partial combustion.
This can be shown with the help of an activity.
If you introduce a glass plate in the innermost zone then a black ring on the glass will be observed, this is due to the fact that this zone contain unburnt wax because of incomplete combustion.
Similarly, If you introduce glass plate in the middle zone then you will observed the same result. This is again due to the presence of unburnt wax vapour i.e. ( partial combustion).
However no such black ring is observed when glass is introduced in the outermost zone which indicates that this is the zone of complete combustion.