Two children, their mother, and aunt enjoy nature during a three-day canoe trip. Tell the students that rivers also shape the land itself. Explain that a river flows from its beginning called its source to the place where it empties into a larger body of water called its mouth . Write the terms on the board. Tell the students the source or beginning of many rivers is rainwater that collects in small hollows or ditches and moves over the surface of the land to form a stream.
Several streams flow together to make a river.
The sources of other rivers are mountain springs, lakes, and glaciers. Direct the students' attention to the Mississippi River on the classroom-size U.S. map. On the map, trace the path of the Mississippi River going north. Point out that there are several rivers that flow into the Mississippi River. Direct the students' attention to the Pacific Northwest area of the United States.