The process of emulsion could be explained as the mixing of two or more liquids which are usually immiscible that is unblendable that they do not get mixed easily. For eg: oil in water, water in oil. It's like a mixture of two substances that do not mix it just that one substance get dispersed in other and forms a cloud like mixture. These mixtures do not form naturally and are unstable.

Basically there are two type of emulsions one is temporary other is permanent. Simple vinaigrette is an example of temporary emulsion where we mix oil and vinegar and they get mix in each other for a short period of time but get separated later on. Whereas mayonnaise is an example of permanent emulsion which contains egg yolk and oil. The yolk and oil slowly get in to each other.

There are substances which act as emulsifier which helps other substances to mix in each other. In a stable emulsion droplets of one liquid get evenly dispersed in other liquid. And the new liquid is thicker than the other two old liquids. At times some fine powder or starch may also help in the process of emulsion. For eg. It is starch in flour that joins butter to the liquid stock. Chocolate is one of those examples which are known by rare people which show the emulsion of milk and coco powder.