Please provide an experience report first.
I tried to get fancy and use a cardboard tube as the body of the rocket, rather than just connecting the balloon directly to the straw. The kids had a great time decorating the tube to look like a rocket, but we weren't able to get much distance with the rocket set up that way. I presume the extra weight added too much friction.
I'd recommend this project.
It cost about $2
It took us 20 minutes
Youngest child was 4 years old
This project was very simple (1)
Share your experience. Positive or negative.