Final answer:
The dispersion of a drop of food color in water is due to simple diffusion where the food coloring molecules move from a high concentration to a lower one until evenly distributed.
Step-by-step explanation:
When a student asks about the dispersion of a drop of food coloring in water, the process is known as simple diffusion. This is a type of free diffusion where molecules spread out from an area of higher concentration to an area of lower concentration until there is a uniform concentration throughout the liquid.
This occurs because molecules are constantly in motion, moving randomly, which results in a spread of color throughout the water without any barriers inhibiting the motion of the food coloring molecules.