Osmosis

• osmosis is the movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration
• a partially permeable membrane has very small holes, so small that only tiny molecules (like water) can pass through
• the water molecules can pass through both ways of the membrane during osmosis, this happens because the water molecules move randomly all the time
• there are more water molecules on one side than the other this is because there is a steady net flow of water into the region with fewer water molecules
• osmosis is a type of diffusion - passive movement of water particles from an area of higher water concentration to an area of lower water concentration