Erosion is the picking up or physical removal of rock particles by an agent such as streams or glaciers. Weathering helps break down a solid rock into loose particles that are easily eroded. Most eroded rock particles are at least partially weathered, but rock can be eroded before it has weathered at all. A stream can erode weathered or unweathered rock fragments.
Activity 1. Demonstrates beach erosion. Using the stream table, make a sand pile at one end and pour water at the other end. Rock the table back and forth to create wave movement. Record observations in the space below.
Activity 2: Get a model glacier from the freezer then move the 'glacier' over the sand. Carefully slide the glacier across the sand and record what the glacier does to the sand.
STREAM TABLE LAB:
WARNING: When you start each of these activities, TAKE YOUR TIME!!! Allow the streams to flow for several minutes!
stream table, in which to model stream erosion and deposition
sand, as a material in which to show the result of erosion and deposition
running water to create the flow of water that will create a stream
1. Move the sand to the end of the stream table near the water faucets.
2. Use your hand to smooth out the sand, making sure it covers about the top two-thirds of the stream table.
3. Turn the water on and allow it to flow from one faucet.
4. Observe the small stream that is forming in the sand.
5. What happened to some of the sand as the water flowed over it? Describe your observations.
6. Where did the sand go? Describe your observations.
1.Move the sand back to the end near the faucets and smooth the sand and use your finger to create a winding, meandering channel. From the top of the stream table. Turn on the water and allow it to go down your channel
2. Where is erosion occurring in the meandering stream? Describe your observations.
3. Where is deposition occurring? Describe your observations.
4. Make a sketch in your journal of the meandering stream and label areas of erosion and deposition.
5. PREDICTION: How would the stream change if the slope of the stream table were steeper? Record as many predictions as you can think of.
7. Use the yellow jack to raise up the stream table to make the slope greater than before and run water, slowly and steadily, from the water pipe. Describe any differences you see in channel development or particle movement from the previous channels created at a shallower slope.
8. PREDICTION: What would the landforms in the stream table look like if two or three water pipes made streams at the same time? Record as many predictions as you can think of.
9. Turn on both faucets. Describe your observations, and make a detailed sketch. Consider details like: Do stream channels merge? Are some channels abandoned? Are flood conditions reached quickly or not at all? Are the deposits at the mouths of the streams large or small?
10. How do you think the Grand Canyon was formed?