Emulsions are formed by mixing two immiscible liquids, meaning liquids that don't readily mix together. Here are two common examples:

1. Oil and water: Oil is nonpolar and water is polar, making them inherently resistant to mixing. An emulsifier is needed to stabilize the mixture.

2. Water and fat: Fat is a type of lipid, which is nonpolar, while water is polar. Just like oil and water, they are immiscible and require an emulsifier to form an emulsion.

Let me know if you would like more examples or information about emulsifiers!