Which zone of a flame does a goldsmith use for melting gold and silver and why?

The goldsmith uses the outermost zone of the flame for melting gold and silver because this zone of flame undergoes the 'complete combustion', which means in this zone maximum heat is generated due to maximum oxidation which helps these metals to melt easily.

[Extra information: When any substances are burnt with the help of oxygen, a hot luminous gas emerges. This gas is called flame.

Examples include kerosene oil, and wax.

Structure of Flame: A candle flame consists of three zones. These are the Innermost zone, middle zone, outer zone. The three zones of a flame have different colours and different temperatures.

The different zones of a candle flame can be described as follows:

1. The innermost zone: It is formed just around the wick of the candle flame as the candle burns. It is also known as the dark zone of the flame. It consists of hot, unburnt vapours of the combustible material. It is the least hot of all the zones. There is no air present here.

2. Middle zone: It is also known as luminous zone. The colour of this zone is yellow. It is moderately hot with limited oxygen supply. Hence, the fuel vapours burn partially and produce carbon particles. These particles then leave the flame as smoke and soot. This zone is the major part of the flame. 

3. The outermost zone: It is also known as the non-luminous zone and it is the zone of complete combustion. It is blue in colour.

The ample presence of oxygen helps in complete combustion. It is the hottest zone of the candle flame and does not contribute to producing light.

The labeled diagram of a candle flame is shown below:



Simply Easy Learning

Updated on: 16-Mar-2023


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