Liquid Columns

Why did some objects sink while some objects floated? Also, why did some objects float in the middle of the columg? Do you think the "mixed" one will separate by Monday?
The reason some liquids floated because the object is lighter then the liquid it self. And the reason for some of the objects sink because it was heavier then the liquid/more dense. Some objects floated in the middle because the liquid at the bottom was more dense then the object, but the liquid at the top is lighter so the only place for the object to go is at the middle. I don't think the "mixed" one will separate, because when you mix the liquids together then the substances will fuse. Therefore the density will fuse together and then they won't separate.