What happens to the tungsten wire directly exposed to the air?

Answer:

But if the heat emitted more than the distribution of the tungsten wire will slowly turn red, more and more bright, and finally to promote the tungsten wire and oxygen in the air reaction, the formation of tungsten oxide and broken, resulting in white smoke

But if the power is necessary to see through the large current, if it is a small voltage, small current, tungsten wire issued by the heat and the heat to reach a balance is also nothing

Depends on whether the power, through the large current in the case of no power is not any change;