How do pop bottle rockets work?

Answer 1

There is water in the bottle and the air gets compressed to launch the bottle into the air, and when it reaches apegy, the parachute comes out and lands the bottle safely.

Answer 2

Pop bottle rockets work by creating a build-up of pressure inside the bottle through a chemical reaction between baking soda and vinegar. The reaction releases carbon dioxide gas, which builds pressure until it forces the bottle to shoot upwards like a rocket. The escaping gas propels the bottle in the opposite direction.