Why does oil and water not mix

Its charge is evenly balanced rather than having one positive and one negative end. This means oil molecules are more attracted to other oil molecules than water molecules, and water molecules are more attracted to each other than oil, so the two never mix.

The food colouring actually sinks through the oil into the water layer as water is more dense than oil. This is the basis for a firework in a glass experiment. The two can be forced to mix by adding an emulsifier which creates a mixture of water with oil molecules spread evenly through it or vice versa.

Use water and oil to demonstrate density. You can make a very simple density jar with just oil and water or use other liquids to make a more complex density column. The immiscibility of oil and water, however, is not related to the difference in density. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads.

Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. Share Flipboard Email. Anne Marie Helmenstine, Ph. Chemistry Expert. Helmenstine holds a Ph. To get around the propensity of oil and water molecules to only pal around with each other, you'll have to make an emulsion , dispersing one of the liquids in the other.

It's possible to create an unstable emulsion through vigorous shaking or mixing ; an example would be an oil-and-water vinaigrette, which separates if left too long on the table. To get a stable emulsion, you'll have to add an emulsifier. An emulsifier is a molecule that has a hydrophobic non-polar end and a hydrophilic end.

The molecules of the emulsifier will surround tiny droplets of oil, attaching the hydrophobic ends to it and leaving the hydrophilic ends exposed so the now-surrounded oil can easily mix among the water molecules. Common food emulsions are stable vinaigrettes that contain mustard and mayonnaise, which uses the molecule lecithin from egg yolks as the emulsifier.