Question

Iron does not burn on heating but iron filings burn vigorously when sprinkled in the flame of the burner. Why?

Answer 1

The matter is that iron, when burned in bulk does not burn as like the burningof it in powder form because wheniron rod is burned then its upper surface atoms get excited only but in powder form its all material gets excited and gives out sparkling light.That is why metals in powder form is used in fire crackers.