Blow Out That Candle (Funky Physics Experiments)

You will need:

1. Birthday candle
2. Bottle
3. Small box

Blowing out a candle kept right in front of
you is quite easy. But do you think it is possible
to blow out a candle if it is placed behind
another solid object? The answer to that is
‘yes’ or ‘no’. Find out how!

INSTRUCTIONS

1. Light a candle and place it on any fireproof table surface.
2. Next, place a small box in front of the candle, and try to blow out the candle by blowing air at the box.
3. Does it blow out?
4. Next, replace the box with a
   sturdy bottle and once again,
   try blowing out the candle by blowing at the bottle.

RESULT

When the box is placed in front of the candle, no matter how hard you try the candle will not go out. However, when you place the bottle instead and blow at it, the candle will go out. This happens because when you blow at the box, the air follows the surface of the box until it reaches the corner. At that point, it separates from the box surface and flows outward. But when you blow at the bottle, there isn’t any edge or corner. As a result, the air tends to stick to the curve of the bottle all the way around, thus blowing out the candle. This is known as the Coanda effect.