River Erosion Gizmo questions 2022

Gizmo Warm-up To begin, check that Mountain stream and Short-term erosion are selected. The Gizmo shows a typical stream that is moving through a hilly area. 1. The two movie cameras ( ) allow you to observe different parts of the stream up close. Click on the left movie camera. What do you see? 2. Now select the right movie camera to see the bank of the mountain stream. What is happening to sediments on the bank? Activity A: Mountain streams Get the Gizmo ready:  Check that Mountain stream and Short-term erosion are selected.  If necessary, click outside the circle to close the zoomed-in view. 1. Calculate: The two red flags are 100 meters apart. Click play to release the barrel. The time at which the barrel passes the flag is shown. Remember, there are 60 seconds in a minute. A. How many seconds did it take for the barrel to go 100 meters? B. To find the barrel’s speed, use a calculator to divide the distance traveled (100 m) by the time it took the barrel to float 100 m. The units are meters per second (m/s). What is the speed of the barrel? 2. Observe: Turn off Show data. Next to River flow, select Flood. Look at the landscape, and then click on the movie cameras to see zoomed-in views. Describe what you notice below. 3. Calculate: Click Play to release the barrel. How many seconds does it take the barrel to get from one flag to the other? What is the speed of the barrel? Time: Speed: Introduction: Meandering rivers are found in flatter areas. Unlike the V-shaped mountain valleys, the valleys of meandering rivers have wide, flat bottoms called floodplains. 1. Observe: Turn off Show labels. Click Play to release the barrel. Observe the path of the barrel as it floats down the river. (The flags are 100 meters apart.) Activity B: Meandering rivers Get the Gizmo ready:  Select Meandering river.  Select Short-term erosion, Low vegetation, and Normal river flow. Turn off Show data. This study source was downloaded by from CourseH on :22:19 GMT -06:00 A. How many seconds did it take for the barrel to go 100 meters? (Remember, there are 60 seconds in a minute.) B. What is the speed of the barrel? C. Turn on Show path. Did the barrel stay in the center of the river or go from side to side? Circle one. D. As the barrel went around each meander, did it stay closer to the point bars or the cutbanks? Circle one. In a meandering river, the water flows faster on the outside of a meander, near the cutbank, and moves more slowly near the point bar on the inside of the meander. The current carries the barrel toward the cutbanks and away from the point bars. 2. Compare: Click Reset. Turn on Show data. List the slope, speed, discharge, and transported sediments of the meandering river. Then select Mountain stream and fill in the remainder of the table. Change back to the Meandering river and compare the values. In what ways is a meandering river different from a mountain stream? 3. Observe: Turn off Show data. Click the right movie camera to see the cutbank. Look at the sediments just above the water. What do you see? Now select the left movie camera to see the point bar. Look at the sediments in the water. What do you notice? Erosion occurs at the cutbank, where water is moving faster. As a result, cutbanks are steep and often overhanging. Sediments are deposited in the slow-moving water near point bars. 4. Compare: Click in the simulation area to turn off the movie camera. Select Flood. A. The flat area surrounding the river is called a floodplain. Why do you think it has this name? B. Why might it be a bad idea to build a house in a floodplain? C. Turn on Show data. How do flood conditions differ from normal conditions?