“You wouldn’t have believed it possible to blow out a candle flame through a brickbat,” remarked a celebrated physicist, whose penchant is to give scientific research a practical bearing. “It can be done, however, and it illustrates the all-pervasive qualities of air. Most rooms are largely ventilated through their walls, and the brick and mortar are merely rudimentary lungs, which take in and throw out the atmosphere with little hinderance.
“You may try the experiment yourself. Place a candle on the other side of your brick and use two funnels, with the flaring ends on the opposite sides of the brickbat with the small end of one in line with your mouth an the small end of the other trained on the candle flame. The least breath will make the light flicker, and a hearty expiration will extinguish it altogether. Try it and see.”
I wonder if you can do it through drywall?