For the indoor demonstration, we will bring the envelope (the big cloth part of the balloon) into your gym (or other suitable indoor area). We will spread the fabric across the floor, and start some electric fans. The balloon will inflate lying on its side. We do not bring propane or the big flame indoors. The balloon will not stand up or fly. Students however, will be very excited to see how big it is. Its size is even more obvious when it is indoors.

But the really fun part is still to come. Once we fill the balloon with air, then we fill it with kids! We take all of the students inside the balloon. With a good sized gym we will be able to accomodate 4-500 students in the balloon at once. Of course, smaller groups are easier to work with, but the balloon is that big.

Now we do not have the students just walk through the balloon. Rather we have them sit down and we show them some things about the balloon they would not be able to see from the outside. We emphasize the weight of the air contained in the balloon, and the weight it can carry. And we show them a little about how the balloon is built (why it doesn't pop if a bird pecks at it) etc. Kids are excited about being inside the balloon, so this presentation is short but very effective. The entire demo takes about 30 minutes.

Video of indoor demonstration