Question

How do molecules of water move during osmosis

Answer 1

The molecules move from a region of higher water potential to a region of lower water potential, through a semi permeable membrane.

Osmosis can be seen as water molecules moving down a water potential gradient. Water potential is the tendency of water molecules movement. The higher the water concentration is, the higher the water potential. This net movement of osmosis will continue until equilibrium is achieved, which is, when the water potential of both sides of the membrane is the same. At that time, water molecules still move, but theres no net movement, that is for example the number of molecules moving from left to right is the same number of molecules moving from right to left.

Osmosis is a natural event, as long as there's a semi permeable membrane, and a water potential gradient. This process doesn't require extra energy. Osmosis is only the movement of water molecules, other substances move by diffusion down the concentration gradient.