Explore the fascinating phenomenon of density in this simple science experiment. Budding scientists of all ages and skills will delight in observing this hands on activity. The experiment gives a fantastic visual interpretation of how different items have different densities and how they interact with one another in the world.
In this activity you will find that oil floats on water because oil is lighter than water. In more scientific terms, water is denser than oil. Density is a measurement of how much a given volume of something weighs. Things that are less dense than water will float in water. Things that are more dense than water will sink.Even though oil and water are both liquids, because the have different densities, they do not mix.
When you add salt to the jar, you will see that in terms of density, salt is heavier than water. So when you pour salt on the oil, it sinks to the bottom of the mixture, carrying a blob of oil with it. In the water, the salt starts to dissolve. As it dissolves, the salt releases the oil, which floats back up to the top of the water.
How to Do It