Introduction to Candle Flame

Candles produce light by releasing heat and all the turn on the candle produces come from a chemical reaction known as combustion in which wax reacts with oxygen in the air to produce carbon dioxide.

The substances that vaporize while burning produces the flame. Kerosene oil and molten wax are the two substances that are responsible for producing flame while burning. Flame is defined as the area of combustion of a combustible substance. Substances that do not vaporize during burning, do not produce the flame.

Structure of candle flame

In a general candle, flame color depends on three factors:

  • Nature of the substance that undergoes combustion
  • Amount of oxygen and
  • Temperature

There are two types of flames:

  1. Non luminous flame and
  2. Luminous flame
Luminous flame Non luminous flame
Incomplete combustion Complete combustion
Color – Bright yellow Colorless
Insufficient amount of oxygen Presence of sufficient oxygen
Provides light Hotter

In a candle flame, a quarter of the energy created is released as heat.

A candle flame consists of three different zones. Each zone has different temperatures. Every zone has different color and this will help us in understanding the temperatures of each zone.

  1. The first zone is called the Outer zone
  2. The second zone is called the Middle zone
  3. The third zone is called as Inner zone

Due to complete combustion, the outer zone is blue in color. This zone is the hottest in temperature when compared to the other zones. This blue colored zone is the non luminous part of the flame.

The yellow color region which is the bright part of the flame is the middle zone. It is moderately hot and partial combustion of fuel takes place.

The least hot region of the flame is present innermost. This inner zone is black in color due to the presence of unburnt wax vapors.