Candle in the Wind Experiment

Set the candle at a height so your mouth is at the same level as the flame. Use a sturdy pillar candle, or stick a birthday candle in a piece of playdough so it won't fall over.

Set the square vase between you and the candle. With your mouth very close to the vase, blow hard. The vase blocks the wind, and the candle doesn't go out.

Now try the round glass. The candle should be a few inches behind the glass, and your mouth should be quite close to the glass.

Blow hard at the glass - the wind will travel around the glass and put out the candle!