The candle flame is divided into three major zones which are differentiated on the basis of their colour and temperature. Following diagram can be used to understand about different zones of a candle flame:

1. Outer most zone: This is the hottest part of a candle flame. It is blue in colour. Here complete combustion takes place due to the good supply of oxygen.

2. Middle zone: This region is moderately hot. It is yellow in colour. Here incomplete combustion of oxygen takes place due to limited supply of oxygen.

3. Dark zone: This region is least hot. It is black in colour. Formation of vapours takes place in this region. Here no combustion takes place.