Materials
- 1 cup (250 mL) water
- 1 cup (250 mL) vegetable oil
- 1 tablespoon liquid dish soap
- Clear glass or jar (tall works best)
- Spoon
Instructions
- Pour 1 cup of water into a clear glass.
- Add 1 cup of vegetable oil on top of the water. The oil will form a separate layer floating above the water.
- Stir with a spoon. Even if you mix for a long time, the oil and water will separate again into two layers.
- Add 1 tablespoon of liquid dish soap to the glass.
- Stir again.
- This time, the oil breaks apart into tiny droplets that spread through the water.The liquid will turn milky and uniform, showing that the oil and water are finally mixing.
What’s going on?
- Oil and water don’t mix because their molecules are different types. Water molecules are polar (charged). Oil molecules are non-polar (no charge). Polar and non-polar molecules do not blend, so oil floats on top of water as a separate layer.
- Dish soap changes everything because each soap molecule has two ends: a hydrophilic end that loves water, a hydrophobic end that sticks to oil.
- Soap acts like a tiny bridge that grabs oil on one side and water on the other.This breaks the oil into tiny droplets that stay mixed with the water.This new stable mixture is called an emulsion.
Tried this experiment?Please consider Leaving a Review!
