AAT Bioquest

What are the different types of mixture based on the size of the particles involved?

Posted March 17, 2023


There are three types of mixtures based on the size of the particle size involved – solution, colloid, and suspension. 


A solution is a homogeneous mixture made up of tiny particles that are less than 1 nanometer in size, which is too small to see. The components of a mixture cannot be isolated by decantation or centrifugation of the mixture. 

Brine is an example of a solution. When salt is mixed with water, it forms a brine solution. The salt particles are no longer visible in the water, and they cannot be isolated by decanting or centrifuging the mixture.


A colloid is a homogeneous mixture composed of medium-sized particles that are large enough to reflect light so you can see them. However, they are too small to settle or to be filtered out of the mixture. Particle sizes in a colloid range from 1 nanometer to 1 micrometer. It looks homogenous without magnification. Under a microscope however, it appears as a heterogeneous mixture.. 

Gelatin is an example of a colloid. The gelatin particles are visible in the mixture but they are too small to settle at the bottom of the dish. 


A suspension is a heterogeneous mixture made up of large particles. The particles are large enough to be easily visible and also to settle or be filtered out of the mixture. Suspensions typically have stabilizing agents that prevent the components from isolating from each other. The components of a suspension can be isolated easily by decanting or centrifuging. 

Salad dressing with oil, vinegar, herbs, spices, and water is an example of a suspension. If the salad dressing is allowed to sit for a while, the mixture will separate into its individual components. The heavier components such as the herbs and spices will settle at the bottom of the dish while the water drifts and rises to the top.  

Additional resources

Solution or suspension - Does it matter for lipid based systems? In vivo studies of chase dosing lipid vehicles with aqueous suspensions of a poorly soluble drug

Buffers and Lab Consumables

ReadiUse™ Staurosporine * 1 mM DMSO stock solution*