Why a tea bag placed in hot water to make tea and swells in size is a model of osmosis?

When a tea bag is placed in hot water, the water molecules move from an area of higher concentration (in the water) to an area of lower concentration (inside the tea bag). This movement of water through a semi-permeable membrane (the tea bag) is a model of osmosis. As the water molecules move into the tea bag, it causes the tea leaves and other contents to swell in size, demonstrating the process of osmosis in action.