Science: Oil and Water don't mix

After a rainstorm we have noticed some puddles in the road with glossy-looking oil floating on top. The boys wanted to if oil ever floats on the water or mixes with it? We decided to conduct an experiment of our own to find out.We placed some water in a pot and added vegetable oil to it. We added table salt so that the boys could clearly see the oil (plus Mommy did not want to stain her good pots