Lag to peak with a stream table
This activity was selected for the On the Cutting Edge Reviewed Teaching Collection
This activity has received positive reviews in a peer review process involving five review categories. The five categories included in the process are
- Scientific Accuracy
- Alignment of Learning Goals, Activities, and Assessments
- Pedagogic Effectiveness
- Robustness (usability and dependability of all components)
- Completeness of the ActivitySheet web page
For more information about the peer review process itself, please see http://serc.carleton.edu/NAGTWorkshops/review.html.
This page first made public: May 27, 2014
Skills and concepts that students must have mastered
How the activity is situated in the course
Content/concepts goals for this activity
- Differences between channel forms on hydrologic processes such as water movement.
Higher order thinking skills goals for this activity
- Analyzing often messy lab data
- Synthesizing data collected into a lab report
Other skills goals for this activity
- Working in a group to collect the data (definitely requires a group effort)
Description and Teaching Materials
Students arrive and I have them determine a flow rate for the water coming in to the stream table. They decide on an input volume, rate, and time to aim for. It doesn't matter much what this is, as long as it is consistent for all trials. They also should determine how frequently they will measure water coming out of the table (we did 20 seconds into a 1 L graduated cylinder for 4 L of water coming in in 20 seconds). They should practice collecting the water and reading volumes out at the intervals determined. It takes a little coordination between the student with the stop watch, the recorder, and two with graduated cylinders (so they can switch back and forth).
They then make one of the three channel forms (either no channel - just sediment, a "concrete channel" (straight and with sediment pushed to the sides), or a meandering channel with sediment on the bottom). They wait for water to stop dripping out the end of the table.
After the table is ready, they turn on the water for their pre-determined input volume and time. Students at the end of the table collect water and read out volumes to the recorder. Keep collecting data until very little (or no) water is coming out of the table.
This is repeated for each of the three channel types. You could add more channel types or different input hydrographs.
Students make hydrographs showing the volume of water that came out in each interval of time (say 20 seconds). They then complete their assignment for the week (write the lab report, edit the report, or make a concept sketch).
This basically models a pulse flood from upstream (say a dam burst) and how different channels respond differently.
Lab handout (Acrobat (PDF) 142kB Oct2 15)