 I'm Eli, I love to have a jar with H2O, you might call it water. I'm going to add some oil. Did you see that? The oil floats on top of the water. I have some sodium fluoride. You might call it salt. Let's sprinkle some onto the oil. Oil floats on water because it is less dense than water. Salt is more dense than water. So the salt sinks to the bottom. The salt takes lots of oil down with it. Then the salt dissolves into the water. That leaves the oil to float back to the top. Now you see why I love science.