Osmosis is the movement of water molecules across a partially permeable membrane down the water concentration gradient.
A partially permeable membrane is a membrane with very small holes in it, only very small molecules can fir through, such as water, bigger molecules like sucrose can't fit through.
Water molecules pass through the membrance both ways because they move randomly. However, it is the net movement that balances the two concentrations.
Osmosis is a type of diffusion- there is a passive movement of water particles from an area of high water concentration to an are of low…