What is the primary characteristic of a colloid?

The primary characteristic of a colloid is that it has particles that do not settle out. This means that when a colloid is formed, the dispersed particles (which can be solid, liquid, or gas) remain evenly distributed throughout the medium and do not precipitate over time as seen in other types of mixtures. This stability is crucial in various applications across beauty and cosmetic formulations, where a consistent texture is needed without separation of ingredients over time.

In a colloid, the particles are typically in the range of 1 nanometer to 1 micrometer in diameter and are small enough that they do not settle due to gravity, creating a stable mixture. This phenomenon can be observed in products like creams, gels, and lotions, where the suspension of particles provides the desired properties for the product.

Other types of mixtures may exhibit different behaviors, such as suspensions, where larger particles can settle out over time, or solutions, where the solute dissolves completely and the particles do not remain suspended in the medium. The characteristic of being unable to be separated by filtration stems from the small size of the particles in colloids, differentiating them from suspensions, which can be filtered to remove larger particles. Thus, the properties that define colloids play