I think that the rocket will shoot into the air because the air needs to escape.
Have you ever heard of a aqua pod?
A aqua pod is orange looking launch pad and is used to launch bottles in the air it also has three legs on the bottom and a flappy part theres string connected to the flappy part.
First you fill up the bottle with about 1/3 of water you have to flip the aqua pod upside down so you can attatch the water bottle to a valve thats almost in the middle of the aqua pod
secondly you have to connect the pump to another valve at the end of the aqua pod to pump air in the bottle you have to stand on the pump 8-12 times to fill the bottle of water with air as you add more pumps of air into the bottle, the air starts to compress and more and more particals start forming
Lastly pull the sting and the flappy part on the aqua pod will hit the thing that the bottle is attachted to and the bottle comes flying off it will go so high it disappeares out of sight
This Science expermement is a reccomend.
