Question

We had an experiment that is entitled "balloon rocket" it is an experiment using the force of balloon to make the straw move. it is about law of interaction.

Did the escaping air have to hit anything to make the balloon move??

my answer here is no, because even in space, space rockets can travel even in a vacuum.

is it correct??

Answer 1

every action has an equal and opposite reaction....when the balloon pushes air out of its nozzle, the air pushes the balloon right back....
in space the rocket fuel comes out of the rocket and goes in the opposite direction to that of the rocket, thus providing the rocket with a momentum to go forward.]
so yes you are right.

Answer 2

There will be some extra propulsion afforded by whatever the air hits. Before / during launch, rockets will be pointed into a chamber closed at the other end. There will be some build up of gas in the chamber on ignition, and this will push the rocket upwards (in addition to actual rocket propulsion). The same happens in the chamber of a gun: the bullet is kept in a sealed chamber to make sure the expanding gases push the bullet out of the chamber.