What is the Difference Between Convection and Diffusion?

The main difference between convection and diffusion lies in the scale and nature of the movement of particles within a medium. Here are the key differences:

• Convection: This is the process of heat transfer through the bulk movement of molecules within fluids, such as gases or liquids. Convection involves the large-scale movement of a mass of particles in roughly the same direction. It requires a driving force, such as a pressure gradient, to generate bulk flow. In convection, all solute molecules move in the direction and with the velocity of the bulk flow.
• Diffusion: This is the movement of single particles and the transfer of their momentum and energy to other particles. Diffusion occurs via the random motion of molecules and is always occurring. It is a molecular-size-dependent process that depends on the size of the molecule and the gradient of concentration. Mixing a drop of ink in a glass of water is an example of diffusion.

In summary, convection is characterized by the large-scale movement of a mass of particles, while diffusion is the movement of single particles and the transfer of their momentum and energy.

Comparative Table: Convection vs Diffusion

The main difference between convection and diffusion is the scale of movement and the driving force behind the transport of substances. Here is a table comparing the two processes:

In summary, convection involves the large-scale movement of a mass of particles, typically driven by heat transfer and occurring in two forms: natural and forced convection. On the other hand, diffusion is the small-scale movement of single particles from a region of high concentration to a region of low concentration, driven by the net movement of particles.