IN the years, prior to the use of candles, people used oil lamps.
In 3000 B.C. for instance, the Egyptians were using wicked candles, but the ancient Romans were credited with developing true dipped candle from tallow.
European candles are antiquity made from various forms of natural fat, wax and tallow. In the present day it is commonly made from
wax with a cotton string in the center that serves as a wick.
When the wick is lit the candle lasts until all the wax melts. The candle flame is formed due to vaporisation of wax upon burning.
The colour of the flame can express the temperature of the flame. In general, there are three distinct zones.
The outer zone in blue colour is the hottest among all zones. This is due to complete combustion of wax taking place in that zone.
The middle zone is yellow in colour with partial combustion of wax taking place. This is due to insufficient oxygen to burn all of the wax.
The inner zone which is above the wick, is the least hot and black in colour. This is due to the unburnt wax vapour. – SCIENCE BRIDGE ACADEMY