Sediment Transportation in Stream Systems
The lab activity and assessments of student understanding of concepts will be demonstrated. The lab activity can be brought to the workshop and all or portions of it completed with participants or demonstrated in a presentation.
My lab activity uses simple stream systems to teach and reinforce concepts in introductory geology courses. Each group of students receives a pvc half-pipe that they partially fill with a sand-gravel mixture to create a stream bed. They are asked to write down hypotheses on effects of changing gradient on sediment. Students then pour water to flow on and through the sediment and create a stream channel and measure gradient and calculate velocity and discharge. They make and label drawings and photos with observations (e.g. locations of sediment erosion, transportation, or deposition, grain sizes, type of stream channel). Students repeat the experiment three additional times, changing a variable each time then answer follow-up questions to assess their understanding of concepts. Outcomes are as follows:
- Demonstrate an understanding of different components or variables of a science experiment;
- Demonstrate and develop critical thinking skills to answer questions or test solutions to problems;
- Demonstrate an understanding of cause and effect relationships in stream systems related to sediment erosion, transportation, and deposition by connecting observations to processes such as changes to stream gradient; and
- Gain real science experiences doing science investigations where the outcomes may not be known.
This is a lab activity focused on teaching introductory level geology course students, including geology majors, and non-geology majors such as education students. The purpose is to introduce and reinforce concepts taught concurrently or previously in a lecture setting.
Why It Works
The simple pvc-pipe stream system is relatively inexpensive compared to other options (e.g. stream tables, etc.) and allows multiple small groups of students to be working simultaneously. Students benefit from small group sizes as every student gains the hands-on experience of exploring stream processes and performing science investigations, yet still work with each other to solve problems that teach and reinforce basic science and stream system concepts.