Where the poop goes

Do u ever wonder why sometimes ur poop floats on top of the water, sometimes it sinks to the bottom and other times u shit and look down and it's no where to be found... Does it have to do with the density of the poop or the type of dump u release... These are the questions that the world must answer... That why I have kidnapped the worlds best scientist and have them working around the clock to figure out the mysteries of the poop locations.. 454