Wind Funnel

Light a candle and blow at it hard through a funnel held with its mouth a little way from the flame. You cannot blow out the flame; on the contrary it moves towards the funnel.

When you blow through the funnel the air pressure inside is reduced, and so the air outside enters the space through the mouth. The blow air sweeps along the funnel walls: if you hold the funnel with the edge directly in front of the flame, it goes out. If you blow the candle through the mouth of the funnel, the air is compressed in the narrow spout, and extinguishes the flame immediately on exit.