Blowing out a candle

QUESTION: Why does a candle go out when you blow on it?

Answer:

As you know both oxygen and a high temperature are needed for burning.

When you blow gently on a flame you may even make the flame brighter. This is because you are blowing oxygen from the surrounding air onto the flame and so it burns well.

If you blow sharply you are once again going to blow in some oxygen but this time also some carbon dioxide and water vapour from your exhaled breath.

However the important difference is that this more intense blow will also produce a rapid cooling. The result of this is that the wick and wax of the candle will fall below its ignition temperature and so the flame will go out.