Detailed Summary
Flame, a visible manifestation of combustion, is characterized by its relationship with different types of fuel. The section explains that various materials can either form flames or burn without visible flames, highlighting commonly used fuels like LPG, candles, and kerosene. Each material burns in distinct manners; for instance, candle wax vaporizes and burns to produce a flame, while charcoal does not vaporize and thus does not enable flame formation.
The section also describes the structural components of a flame. It identifies three zones within a candle flame: the dark zone (unburnt wax vapours), the luminous zone (where carbon particles create a yellow glow), and the non-luminous zone (the hottest, where complete combustion occurs). Experiments demonstrate these zones and clarify that the nature of the flame varies with the substance that is burning, showcasing the differences in combustion between various fuels.
Lastly, the significance of understanding flames is emphasized, especially regarding safety and pollution related to fuel combustion. This knowledge helps in utilizing fuels effectively and responsibly, minimizing environmental impacts.