Slope and Erosion

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Objective

SWBAT use a model to describe the relationship between slope and erosion.

Big Idea

How does the slope of a mountain affect the amount of erosion?

Introduction

5 minutes

I began by showing a few good examples of diagrams for the Erosion lab we did in the last lesson, and compared it to a few that weren't as good.  I asked them to share what they noticed, and when they said "That one is better," I continued to ask probing questions to get them to notice the drawings were neat and the labeling was clear.

Next I shared today's focus question with them, "How does the slope of the mountain affect the amount of erosion?"  While I passed out the Slope and Erosion Investigation Sheet, I had them share predictions with their table.

Engagement

30 minutes

I take them up to the science lab and have "getters" get their supplies for their table.  They can start building right away while I prepare rinse buckets and water bottles.

As with many previous investigations, I'd like to spend our time in the lab making observational assessments, but my main responsibility becomes keeping groups moving forward.  I try to refer them to the written directions as often as possible, and remind them to record their data at each step.

I do encourage them to share what they are noticing, but only when I come over to their table (otherwise they would swarm).  This lesson also lends itself to measuring with degrees of precision.  When my students said, "It's about 2 cm," I went right over and helped them understand how to measure to tenths of cm.  They were able to record the measurement more accurately without having to stop and do a decimal place values lesson.

Closure

10 minutes

I have them clean up and return to the classroom before answering the final page of the investigation sheet because a few groups need a more definite closure of the hands-on portion, or they would be there indefinitely.

When I collect science notebooks, I'm looking to see if they explained that the steeper mountain had greater erosion with a reference to their data.  I'm also looking to see if they notice the water moves more sand and "dirt," and that the pebbles are not affected as much.

If I were to do this lesson again, I would have students share their data with the class by adding their data to a table like this one:

 

Canyon Depth with a Steep Slope (cm)

Canyon Depth with a Gentle Slope (cm)

Table 1

 

 

Table 2

 

 

Table 3

 

 

Table 4

 

 

Table 5

 

 

Table 6

 

 

This could then be turned into a bar graph to create a visual representation of the data.