Water molecules consist of one hydrogen atom and two oxygen atoms. Hydrogen has a positive charge, while oxygen has a negative charge. Since opposite charges attract, the hydrogen atom of one water molecule will attract the oxygen atoms of another water molecule, while the two oxygen atoms of the molecule will attract the hydrogen atom of yet another water molecule. With all the water molecules behaving this way, the "network" of connected water molecules create a barrier to non-water molecules. Soap has the ability to break these connections, allowing water to become permeable to the molecular structure of other objects, such as oil. In this science fair project, the soap allowed the oil and water to mix. This is why soap is used on oil spills and why we use soap when we wash ourselves, dishes, or clothes.
- A large drinking glass, jar, or beaker
- Vegetable oil
- Liquid soap
Fill three quarters of the jar with water.
Pour a small amount of vegetable oil into the jar, just enough to raise the fluid level of the jar but allowing enough space to prevent the jar from over flowing.
Observe how the oil and water remain separate from each other.
Add a small amount of liquid soap, just enough to cover the liquid surface.
Mix the jar and observe what happens to the oil and water.