A suspension is a heterogeneous mixture of a solid and a liquid medium in which the solid does not completely dissolve but is distributed in small particles throughout the medium. The particles range in size from 1 to 1000 micrometers and cannot be seen with the naked eye. Examples of suspensions are sand in water or dust in air.

An important property of suspensions is their stability. Since the particles are heavier than the liquid medium, they tend to settle at the bottom of the vessel. This process is called sedimentation. If the suspension is left undisturbed, the particles can accumulate in a dense layer at the bottom of the vessel. To avoid this, suspensions are often maintained with a stirrer or by shaking.

Suspensions can be separated by filtration or centrifugation. During filtration, the suspension is forced through a filter that retains the particles while the liquid medium passes through. During centrifugation, the suspension is spun in a centrifugal field, causing the particles to settle to the bottom of the vessel.

Suspensions are used in many applications, such as in medicine, in the food industry and in the production of paints and pigments. In medicine, suspensions can be used as medicines to enable a slow and controlled release of active ingredients.

Overall, suspension is an important type of heterogeneous mixture used in many applications. Knowledge of the properties and possible uses of suspensions is important in order to optimize their application and avoid undesirable effects.