Question

name:
date:
student exploration: river erosion
vocabulary: cutbank, discharge, erosion, flood, floodplain, meander, meandering river, oxbow lake, point bar, river speed, riverbank, riverbed, sediments, slope, tributary, weathering
prior knowledge questions (do these before using the gizmo.)

1. the image above shows a raging mountain river in full flood. what do you think is making the water brown in color?
2. what impact do you think the flooding river will have on the surrounding landscape?

gizmo warm - up
if you stand by the bank of a river, it may seem that very little is happening. but over thousands and even millions of years, rivers can have a profound effect on the landscape. in the river erosion gizmo, you will see how rivers move materials and how they affect landscapes.
to begin, check that mountain river and short - term erosion are selected. the gizmo shows a typical river that is moving through a hilly area.

1. the two movie cameras ( ) allow you to observe different parts of the river up close. click on the left movie camera. what do you see?
2. sediments are small rock fragments such as sand or pebbles. what evidence do you see that sediments are being transported?
3. now select the right movie camera to see the bank of the mountain river. what is happening to sediments on the bank?

Explanation:

The problem is about river erosion, which falls under the subfield of Geography (Natural Science). For the first prior knowledge question, the brown color of the water in a flooding mountain river is typically due to sediments (like soil, rock fragments) being carried by the river. When a river floods, it has more energy to erode the riverbed and banks, picking up these sediments and making the water appear brown.

Answer:

The water is brown because it is carrying sediments (small rock fragments, soil) eroded from the riverbed, banks, or surrounding landscape.