The stages of a river
Rivers are made when precipitation, like rain or melted snow and ice, runs down a mountain. The water follows the shape of the land all the way to the sea, a lake or another river. A river has three stages, called courses.
The beginning. It starts at the source, high in the mountains. The land is steep, so the water flows quickly. The river is small, and there can be waterfalls.
The river gets bigger and wider and begins to slow down, because the land is flatter. It often makes meanders: curves one way and then back again.
The last stage. The river is even wider and flows more slowly. It empties into a sea, a lake or another river. This place is the mouth.
Because the land is very steep. Think of a slide: you go much faster on a steep slide than on a flat one! When the land is flatter, the river slows down.
Source: where the river begins · waterfall: where the water falls from a high place · meander: a big curve · riverbed: the land the river flows over · mouth: where the river ends.