Fun for about a dollar.

Business card trimmed for rudder.

LIFT: 9" helium-quality balloon filled with helium and tied.

BALLAST: Modeling clay.

Two 10" long drinking straws (.235" diameter).

¼"

Cellophane tape joins two straws. (Make sure one straw fits into another.)

PROPULSION: 9" helium-quality balloon filled with air and slipped onto straw (neck of balloon trimmed).

UP, UP, AND AWAY!

WARNING: Without ballast,
the blimp will continue
to rise.

Illustration by John Perez

Launch gently.

After bottom balloon runs out of air, the clay weight will cause the blimp to sink.

Illustrations by John Perez