Okay, so I've been wondering about the Galileo experiment for some reason and I can't get my head around how it would work under different circumstances. 1. Is Galileo's experiment only valid in vaccum or is it valid for all kinds of fluids? Also, must the two objects be of the same material/density as well as volume? I personally think that they must be the same volume if dropped in a fluid (I don't think volume matters in a vaccum) but I'm not 100% sure. 2. If I used 2 balls of the same volume and shape but different mass, and dropped them in water, would they both reach the bottom at the same time (assume that their densities are both higher than water)? I tried to using net force = gravitational force - buoyancy but found that their accelerations are different, can someone explain why if this is true or perhaps I messed up somewhere? I thought that the acceleration of both objects should be the same if their volumes are the same. Any help is appreciated. Thanks.