A river begins at what’s called “the source” and ends at “the mouth.” The mouth of a river is where it connects with a bigger river, lake, or even the ocean.
When soil erodes (moves) from the land into rivers, it can be carried a long way in the moving water. Believe it or not, some eroding soil in Illinois winds up as far away as the Gulf of Mexico.
This satellite image shows the Amazon River (the black lines) flowing into the Atlantic Ocean. The “mouth” is where a river flows into a larger body of water.
Photo: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC
The green line snaking up across this satellite image is the world’s longest river, the Nile. It enters the Mediterranean Sea at its “mouth.” The Nile River’s mouth is hidden by that big patch of green (vegetation along the river).
Photo: Jacques Descloitres, MODIS Land Science Team, NASA
That brown line moving from the top left across this satellite image is the Mississippi River--the “Big Muddy.” It flows into its “mouth” in the Gulf of Mexico, carrying lots of soil. Look closely and you can see brown soil entering the Gulf right at the river mouth.
Photo: Jacques Descloitres, MODIS Land Science Team, NASA