Does vegetable Oil have a higher density than water?
I am assuming that you are using some of those air pumped rockets that you put water in, is this correct? What your experiment is going to show is Newton’s Third Law. Simplified: Every action has a reaction. So the denser liquid will make the rocket go up higher if both liquids are ejected at the same rate. Since the mass of the liquid ejected is the equal to the force propelling the rocket. When you do the experiment, make sure that you are pumping the rockets to the same pressure to get valid results. Some things that might affect your results also is the viscosity of the liquid. You might want to try liquids of different viscosities also like rubbing alcohol, vegetable oil and motor oil since all those are less dense than water but all have different viscosities.
