To begin this lesson, I ask students to consider the streams and rivers in our local area. I ask them to work with their science groups to compare the Columbia River (a large river leading to the Pacific Ocean) to Salmon Creek (a tributary of the Columbia River that our class frequently visits). After students compare the two streams, I ask them to consider whether they think the size of the stream affects the amount of erosion that occurs in the stream system. I ask students to consider this reflection as they conduct the day's lab.
In this lab, students will examine the effect of stream size on erosion. To do so, they will compare their results to their findings from a previous lesson.
I begin the lab by displaying the exploring flow lab worksheet on the document camera. I review the materials to be used in the lab and the procedures for conducting the lab. Prior to allowing students to begin work on their lab, I have them copy the results from their lab on streams onto their lab sheet. The students will use these results to conduct a side-by-side comparison of their results from the streams lab to today's findings.
I provide students with time to conduct the lab, while circulating around the classroom to provide technical support and to answer student questions as they arise.
An example of a student's complete lab work can be found here.
To close the lesson, I ask students to use the evidence they recorded on their lab worksheet to justify their conclusion about the effect of stream size on erosion. I ask students to use observational data from their stream table drawings and data in the form of stream measurements to support their thinking. I ask each student to record a conclusion paragraph on their lab worksheet. I use this as a formative assessment tool to ascertain whether or not students have determined the relationship between stream size and flow and rate of erosion.
A video of my students discussing their results can be found here.