Describe the process of osmosis.

Osmosis is the net movement of water molecules from an area of higher water concentration to an area of lower water concentration across a semi-permeable membrane.

Step-by-Step Solution:
Water molecules move through a semi-permeable membrane that allows water but not larger molecules to pass through
Movement always occurs down a concentration gradient (high to low water concentration)
Process continues until equilibrium is reached (unless stopped by other factors)
Can be demonstrated using potato chips in different sugar solutions showing mass changes

Key Mistake to Avoid:
Don't confuse osmosis with active transport or diffusion of solutes - osmosis ONLY refers to water molecule movement.

(Required practical variations may differ)

Quick Tip:
Draw and label a simple diagram showing water molecule movement across a membrane - examiners love to see this in practical-based questions.