Definition:
- A colloid is a type of mixture where particles are dispersed in a medium, but they do not settle down due to gravity. The particles are larger than those found in a solution but smaller than those in a suspension.
- A suspension, on the other hand, is a heterogeneous mixture in which solid particles are dispersed in a liquid or gas, and they can be easily seen and separated by gravity or filtration.


- Colloid: The size of particles in a colloid ranges from 1 nanometer to 1 micrometer, making them smaller than those in a suspension but larger than those in a solution.
- Suspension: Suspensions contain larger particles, typically ranging from 1 micrometer to 1000 micrometers (1 millimeter). These particles are visible to the naked eye and can settle down due to gravity.


- Colloid: Colloids are relatively stable and do not settle down under normal conditions. The dispersed particles remain suspended due to the Brownian motion, which is the random motion of particles caused by collisions with molecules in the medium.
- Suspension: Suspensions are unstable and tend to separate over time. The solid particles settle down due to gravity, leading to a visible sediment at the bottom of the container. Agitation may temporarily suspend the particles, but they will eventually settle again.


- Colloid: Colloids appear homogeneous to the naked eye. They may have a cloudy or milky appearance, but the particles are not individually visible.
- Suspension: Suspensions are heterogeneous and appear cloudy or opaque. The solid particles are clearly visible and can be observed settling at the bottom if left undisturbed.


- Colloid: Colloids cannot be easily separated by filtration, as the particles are smaller than the pores of filter paper. However, they can be separated through specialized techniques such as centrifugation or dialysis.
- Suspension: Suspensions can be separated by simple filtration, as the particles are larger and can be trapped by filter paper. Alternatively, they can settle down over time, allowing for separation by decantation or sedimentation.


- Colloid: Colloids exhibit the Tyndall effect, which is the scattering of light by dispersed particles. When a beam of light passes through a colloid, the path of the light becomes visible due to the scattering of light by the colloid particles.
- Suspension: Suspensions also exhibit the Tyndall effect, as light is scattered by the suspended particles. The path of light becomes visible, indicating the presence of particles in the suspension.

Overall, the main differences between colloids and suspensions lie in the size of particles, stability, appearance, and the ease of separation. Colloids have smaller, dispersed particles that do not settle down easily, while suspensions have larger, visible particles that settle over time. Colloids appear homogeneous, while suspensions appear heterogeneous. Colloids require specialized techniques for separation, while suspensions can be separated by simple filtration. Both colloids and suspensions exhibit the Tyndall effect, indicating