The forces acting are unbalanced. The rocket launch is a very good example to look at when considering Newton's First and Second Laws. When preparing for launch, the rocket is stationary.

It can potentially change the way we approach space exploration and even redefine the laws of physics as we currently know them! Propellant-less Rockets ... This defies Newton’s third law ...

The class could then construct water rockets and observe Newton’s third law in action. They could investigate the optimum ration of water to air volume needed for the highest flight. Include a ...