The problem with a lot of these water bottle rocket projects is that they leak where the bottle meets the launcher. In most cases this is a good thing as it’s almost impossible to build up ...

For that price you can make 4 rockets for the launcher, as the foam sleeping pad ... Foam Sleeping Pad 6. 2 Liter Soda Bottle 7. Duct or Packaging Tape 8. Hot Glue 9. Drill & Bits 10.