Blow over the top of the pipe. The air flowing over the top of the pipe will reduce the pressure there (called the Bernoulli effect), causing a pressure imbalance that will cause the ball to rise. I'm not sure just how hard (or how long) you'd have to blow to get enough of a pressure differential to get the ball to fly all the way out of the tube; it may be more than is reasonable to expect a person to blow. My first thought on all this was to perhaps use the match to burn something (maybe the string?) over the top of the pipe, using heat to achieve a similar effect. Again, I'm not sure how the magnitudes of the force required would compare.