After her victory against an "18-inch" (nominal) balloon, and a needed change of attire, MJ is ready for a greater challenge. A double-stuffed pair requires twice the pressure, and yet she elects to try it without the check valve. She records this data run overlaid on the single balloon to show the difference in pressure requirement. Again, she sets a brisk pace and puffs relentlessly, with cheeks bulging and face reddening, until she reaches a point of uncertainty. She pulls her mouthpiece off, which stops the flow out from the balloon, and after a break of only a few seconds, installs the...

After her victory against an "18-inch" (nominal) balloon, and a needed change of attire, MJ is ready for a greater challenge. A double-stuffed pair requires twice the pressure, and yet she elects to try it without the check valve. She records this data run overlaid on the single balloon to show the difference in pressure requirement. Again, she sets a brisk pace and puffs relentlessly, with cheeks bulging and face reddening, until she reaches a point of uncertainty. She pulls her mouthpiece off, which stops the flow out from the balloon, and after a break of only a few seconds, installs the check valve, and then her mouthpiece. A few mighty puffs later and she is rewarded with an even more dramatic explosion than the first balloon produced. She catches her breath with a broad smile.