Final answer:
The addition of blue food coloring to water is an example of diffusion, where the food coloring molecules evenly distribute due to their kinetic energy. Other related experiments can show the effects of convection alongside diffusion with varying temperatures.
Step-by-step explanation:
The student's experiment of adding blue food coloring to water is an example of diffusion. When the coloring is added to water, its molecules move from an area of higher concentration to areas of lower concentration until they are evenly spread out. This is a natural process observed at the molecular level where substances move towards equilibrium without any energy input outside of their kinetic energy.
In a related experiment, heating one pot of water while leaving another at room temperature demonstrates convection rolls. In the heated pot, the food coloring spreads more quickly due to the formation of convection currents driven by temperature differences within the water, showing both diffusion and convection at work.
This principle of free diffusion is seen when food coloring spreads evenly throughout water without any barriers to movement, and the rate is highest initially and slows down as the concentration becomes uniform across the water.