Material A compact disk, CD, music or CD-ROM disks both work. The mouthpiece to a sport water bottle. The kind that pull to open and push to close. Put the label side of the CD down toward the table. Hot melt glue the film can over the hole in the CD with the smooth side of the film can lid up.
Hot melt glue the water bottle mouthpiece to the top of the film can lid.
Blow up the balloon. Twist the neck of the balloon to keep the air from escaping and stretch the neck over the water bottle mouthpiece. Make sure the water bottle mouthpiece is closed. Cut a length of toilet paper tube long enough so that it will push against the bottom of the balloon and keep it from flopping over. The balloon supported by its paper collar.