Osmosis only talks about water molecules
Diffusion talks everything other then the water molecules.
So,
Osmosis : water molecules travel from a region of a higher water potential to a region of lower water potential through a partially permeable membrane via osmosis
Diffusion : Travels from a region of higher concentration to a region of lower concentration through a partially permeable membrane via diffusion
The flow of energy starts in in you arms. You put your hands together, and use your arms to move your hands back and forth, this is kinetic energy. Your hands rubbing together causes the molecules to bump into each other, this is friction. As the molecules bump into each other they begin to move faster, and the fast movements of the molecules is what creates heat.
