Chemistry
The open "Sigrees" or coal stoves often require fanning to sustain burning because of

Accumulation of smoke and dust over the sigrees
Lack of oxygen in the surroundings of sigrees
Tendency of carbon dioxide to form a layer along with dust smoke
Interrupted release of moisture from the material

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Chemistry
Metal are good conductors, because

They contain reflecting surface
The molecules in them collide very freely
They contain free electrons
The molecules in them are very close to each other

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