More ideas from yunzhi
Elytron Aircraft SAFE FAST SIMPLE

Elytron tiltrotor airframe completed on wordlessTech

Super-fun balloon rockets also teach an important science lesson.

Balloon Rockets - I've done this in several science camps I've conducted. Kids have fun with it. But, when the balloon deflates it may fall off the straw because it's surface area changes - another good thing to show and explain to kids.