Up, up, and away!
Fit one straw end into the other, overlapping about ¼”, and seal with tape.
Bend one end of the straw into a “U” shape, using a piece of tape to hold it in place. (Bendy straws work well.) This is the front of your blimp.
Trim the business card into a rudder shape and use tape to attach it to the straw end opposite the “U” shape.
Fill one balloon with helium and attach with tape to the front of the blimp, toward the “U” shape. Don’t let go!
Add modeling clay until the blimp slowly starts sinking to the ground.
Without ballast, the blimp will continue to rise.
Blow up the second balloon with air and slip it onto the shorter end of the “U” shape. Make sure not to let the air out and that the neck of the balloon fits snugly on the straw.
Launch gently.
After the bottom balloon runs out of air, the clay weight will cause the blimp to sink, so you can grab it and do it again!
Conclusion
This project first appeared in MAKE Volume 03, page 42.
