Is momentum conserved in a liquid? It seems to me that if you shoot a bullet into a tub of water less momentum will be transferred than if you shot into an empty tub. Most of the kinetic energy will decay to heat and with it a part of the momentum. When the bullet goes in it creates some kind of shock wave in the liquid. This shock wave is composed of particles moving back and forth. If you treat the particles like tiny little marbles it isn't impossible to see how some of the linear momentum would get scattered. The experiment - put a container of water on one of those air-tracks common to high school physics labs. Shoot at it with a bb gun empty and full and record momentum. Seems like momentum may get conserved but scattered; hence everything but the vector component of the momentum is conserved.