When water and chalk mix, they form a suspension. A suspension is a mixture in which solid particles are dispersed throughout a liquid. The chalk particles are too large to dissolve in the water, but they are small enough to remain suspended in the liquid. This means that the chalk particles will not settle to the bottom of the container.

Suspensions are different from solutions in that the particles in a suspension are not dissolved in the liquid. In a solution, the particles are too small to be seen and they are evenly distributed throughout the liquid. Suspensions are also different from colloids in that the particles in a suspension are larger than the particles in a colloid. Colloids are mixtures in which the particles are too small to be seen but they are not evenly distributed throughout the liquid.

When water and chalk mix, the chalk particles will eventually settle to the bottom of the container if the mixture is left undisturbed. This is because the chalk particles are denser than water and they will therefore be pulled down by gravity. However, if the mixture is stirred or shaken, the chalk particles will be dispersed throughout the liquid again and the mixture will remain a suspension.