For the first experiment on weathering and eroding we took a look at what kind of erosion can take place when water runs off the Earth's surface. To record the video I set up a tripod above the glass aquarium to get a good top-down view of the action. I placed my web cam on the tripod connected to my laptop. I streamed the video from my laptop to Ustream. When I was ready to do the investigate, I hit the record button on Ustream to record it. Because of of the size of the aquarium, I used a 2 gallon bucket of water to simulate water run-off. I used my digital camera to take pictures to record what the web cam could not.
Here is a picture from the top down taken before I poured the water on the model. The soil was created using four substances: humus, sand, gravel, and clay. I added water to make the soil more realistic. The water I mixed in also helped keep all the water I poured on the model from being absorbed into the soil. Although you may not be able to see from this angle, I also slightly sloped the soil so the water would be able to run-off.
Here is the video of the water being poured on the soil. Notice the path the water takes. When the water is done moving, can you tell where the water was?
Here is a top down view. Compare it to the original picture taken before the water was poured onto the model. Can you see a difference? How is it different?
This is a side view of the model. Notice the water under the surface of the soil. How did that water get there? What is that water called? Do you think the water stayed there, or did it move later?
Here is a picture of the bottom of the model where the soil ended. Describe what you see. How is it different than before the water ran over it? In the top part of the picture is where the water ran off. Why is it so dirty? What do you think is in the water that makes it so dirty? Does this help illustrate the watershed concept?
This is a close-up picture of the soil after the water ran off it. What do you see? Is the soil still mixed up or has it separated? Does this look like a stream bed?
Now that the experiment has been completed, what could we change to create a new experiment? Does this model help you with the part of the water cycle that takes place on the surface of the Earth?