# Humans as Geomorphic Agents

Catherine Riihimaki
,
Drew University
Author Profile

#### Summary

An introduction to order-of-magnitude calculations and reading quantitative journal articles.

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## Context

#### Audience

Introductory quantitative course in environmental science

#### Skills and concepts that students must have mastered

Comfort with algebra

#### How the activity is situated in the course

This is the first problem set of the semester

## Goals

#### Content/concepts goals for this activity

understanding order-of-magnitude calculations and dimensional analysis

#### Higher order thinking skills goals for this activity

critical reading skills of peer-reviewed literature, connecting calculus concepts to plot interpretation

#### Other skills goals for this activity

group discussion of peer-reviewed article

## Description of the activity/assignment

1) The students read an article from the literature on humans as geomorphic agents as an introduction to order-of-magnitude calculations.
2) The class discusses the article in a 50-minute class
3) The students complete a problem set that introduces them to dimensional analysis, walks them through a comparison of the article's results to natural geomorphic rates, and explores how the author derived the article's final numbers.
4) Once the students are done with the problem set, the class discusses the results and implications as a group.

## Determining whether students have met the goals

Evaluation is based on the problem set answers and the quality of the discussion.

## Teaching materials and tips

• Activity Description/Assignment (Microsoft Word 66kB Aug1 08)
• Pre-activity preparation includes examples of order-of-magnitude (back-of-the-envelope) calculations. I also explain how to visually (geometrically) measure the area under a curve, and what this number means (calculate total earth-moving from rate of earth-moving). I do not emphasize strategies for reading scientific papers, because this paper is fairly straight-forward.

The paper discussion includes each student's one-word reaction to the paper (interesting, boring, frightening, etc.). We also discuss an example calculation that would have been used in the paper, such as how you could calculate earth-moving for Roman road system. We look at plots to ensure that the students understand that unintentional earth-moving is more significant than intentional earth-moving. Finally, as motivation for the problem set, I make sure they understand that a comparison is needed to assess whether the human earth-moving is "a lot" or "problematic." We return to a discussion of this topic after the students complete the problem set.
• Solution Set (Microsoft Word 82kB Jul29 08)

## Supporting references/URLs 