An emulsifier is a substance that stabilizes and facilitates the mixing of two immiscible liquids, such as oil and water, to form a uniform and stable emulsion. It works by reducing the surface tension between the liquids, allowing them to blend and remain mixed without separating. Emulsifiers are commonly used in food products, like salad dressings and mayonnaise, to achieve a consistent texture and prevent separation. In cosmetics and pharmaceuticals, they help to evenly distribute active ingredients in creams and lotions. They are also used in industrial applications, including paints, coatings, and detergents, to enhance product stability and performance. Emulsifiers are typically surfactants, such as lecithin, polysorbates, or soap, and are essential for creating stable, high-quality emulsions in various products.