Question on: JAMB Physics - 2020

The correct answer is diffusion. Here's why: * **Diffusion:** This is the process where particles (in this case, salt molecules) move from an area of high concentration (where the salt grains are initially) to an area of low concentration (the surrounding water), eventually spreading out evenly throughout the water. * **Convection:** Convection involves the movement of fluids due to temperature differences. This isn't the primary mechanism here, as the water temperature is kept constant. * **Osmosis:** Osmosis is the movement of water molecules across a semipermeable membrane, driven by a concentration gradient. While there is a concentration gradient in this scenario, osmosis does not explain the spreading of salt molecules. * **Capillarity:** Capillarity is the ability of a liquid to flow in narrow spaces without the assistance of, and even in opposition to, external forces like gravity. This is not relevant in the spreading of the salt in the water.