diffusion
net movement of molecules or atoms from a region of high concentration (or high chemical potential) to a region of low concentration (or low chemical potential)
backscatter
reflection of waves, particles, or signals back to the approximate direction from which they came
osmosis
movement of water towards to more concentrated compartment
acoustic diffusion
spreading of sound energy evenly in a given environment
facilitated diffusion
biological process
gas exchange
process by which gases diffuse through a membrane
imbibition
the taking up of fluid by a colloidal system resulting in swelling
surface diffusion
general process involving the motion of adatoms, molecules, and atomic clusters (adparticles) at solid material surfaces