moving around very fast. Collisions between the molecules makes the particles of the fluid change directions and speeds often and randomly. We’ve talked about two different phenomena that depend on these random molecular interactions: viscosity and diffusion. Viscosity is the way collisions with other parts of the fluid slow down faster-moving bits of fluid, and diffusion is the way collisions spread out concentrations of molecules. Let’s consider how the viscosity and diffusion coefficients might depend on the properties of the fluid by dimensional analysis
What are the units of viscosity, in base SI units (kg, m, s)?
What are the units of the diffusion coefficient, in base SI units (kg, m, s)?