"The balloon used in this demonstration was not fully inflated. Fully inflated balloons will not behave in the same manner. The laser does not pop the transparent balloon because the energy of the laser beam light passes through it virtually unhindered. In the bonus clip the balloons pop because they are darker and opaque. Material that is generally darker, opaque and not overly reflective absorbs the light energy and converts it into heat. The heat burns the balloon and causes it to fail and pop."