Download The Oregon Trail and the Geology of the Cascade Mountain Range

The Oregon Trail and the Geology of the Cascade Mountain Range
Grades 6-8:
Standards Assessed:
PA ASST:
NSES:
3.2.7B – Apply process knowledge to make and interpret observations.
3.5.7A – Describe earth features and processes: Describe the processes involved in the
creation of geologic features
6.1 – Abilities necessary to do scientific inquiry.
6.4 – Structure of the Earth System
Instructional Goals:
 Interpret a topographic profile
 Identify geologic characteristics that lead to volcanism
 Identify different tectonic settings, i.e. plate boundaries
Materials:
 “My Dynamic Planet” CD-ROM
 Personal Computers (to use in small groups)
 Model of subduction zone (optional)
 Topographic profile activity sheets
 Rulers, pencils
The “Big Idea”:
We are teaching to students at a middle school level (grades 6-8). We will be teaching the students the
fundamentals of a topographic profile. We will be using this information to relate the importance of
topography to the Oregon Trail. Relatedly, we will be covering the subduction zones of the west coast
of the United States and, consequentially, how the Cascade Mountain range/volcanoes have formed.
What the teacher must know:
In order to teach this lesson plan, as teachers, we need to know the characteristics of a subduction
zone, i.e. the trench, mountain building, location of magma chambers, density differences between
oceanic and continental crust, etc. It is crucial to know how the process of subduction works in order to
fully explain it to the students, i.e. that the ocean crust subducts under the continental crust because it
is denser; the friction of the plates causes heating and volcanism; and the ocean crust pushes up the
more buoyant continental crust to form mountains. Also, we must know how a topographic profile is
created and how to interpret it in order to help the students with their understanding. We must also
have sufficient knowledge of the technology that we plan to use to engage the students.
Administrative Concerns:
A classroom management issue that we must be careful of is to make sure that the students do not fight
over the computer when the program is being run. To avoid this issue, we will make sure that we give
each student an opportunity to use the computer model. This lesson plan was designed to be a very
visual-oriented lesson. We plan on using models on the computer, on paper, and in 3D. This heavy
amount of visual aids should help students overcome language barriers.
Required Materials:
We will need a computer with the program “Our Dynamic Planet” installed and ready to use on it,
preferably one of the computers with larger screens so that all of the students can see the program.
Also, we will be providing a 3D model cut out of Styrofoam of the area from Mount Hood to the
offshore trench in the Pacific Ocean. We will be giving the students handouts of a graph with the data
axis labeled along with data points for them to plot so that they can create their own topographic
profile when they smoothly connect the dots.
Body of the Lesson
A. Engagement (3-5 mins):
 On the map, can you locate the general area where the path of the Oregon Trail went through?
 What are the highest points that the travelers had to encounter on their path?
 Why do you think the mountains are on the coast?
 Do you think there is any topography on the ocean floor, too?
B. Exploration (5-8 mins):
 How would you explain the topographic features that you see on the profile?
 We will have the students create a profile of the area from Mt. Hood to the Pacific trench using
the program “Our Dynamic Planet.” We’ll direct them to start one end of the profile in the
ocean (past the topography of the ocean) and end the profile after the first set of mountain
ranges (i.e. in the general vicinity of Mt. Hood). We will then proceed to ask the students what
they are looking at when the profile comes up.
 After this, we will look at the 3D model to compare what the side of the model looks like
compare to the profile that they found using “Our Dynamic Planet.”
 We will then have the students plot data points (which will be given to them) on a blank graph
(with scales and data axis already labeled for them), after which they will smoothly connect the
dots to make the finished profile. This will help put a more practical scale to the models.
C. Explanation (5-8 mins):
 We will then have a discussion with the students about why the topographic features exist,
primarily asking them to give us any and all possible solutions. After this, we will introduce the
students to various computer animations of plate boundaries and have them explain to us what
is occurring in each animation.
http://www2.wwnorton.com/college/geo/egeo/animations/ch2.htm (plate boundary animations)
D. Evaluation (2-3 mins):
 By the end, the students should be able to tell us which is the correct plate boundary animation
of the given options that would explain the topographic features seen around the Cascades and
the nearby trench in the Pacific. They will also explain in their own words the actual interaction
that is going on between the two plates (i.e. one plate is subducting under the other, pushing up
the mountains, and causing volcanism). If the students give a different response, we will guide
them towards the correct response or ask their classmates to help them find the correct
explanation.
E. Elaboration (0-5 mins):
 After viewing the four different animations and fitting the subducting animation with the
formation of the Cascades, we will ask them to try to explain what is occurring in the other two
animations. Also, we will ask them where they think the other processes seen in the animations
might be occurring in the world using “Our Dynamic Planet” as a map. We can then test their
hypothesis by taking more profiles of the regions where they think these processes occur.
Topographic Profile: Pacific Ocean to Mount Hood
4
Elevation (km)
3
2
1
0
Sea level
-1
-2
-3
-4
-300
-200
-100
0
100
Distance (km)
Data Points:
Elevation (km)
-1.3
-2.5
-1.8
-1.4
0
0
1.0
3.43
1.0
Distance (km)
-300
-200
-150
-100
0
100
175
212
225
200
300
Fun Facts about Mount Hood!
(from http://www.mthood.org/facts.html)
 Mt. Hood is the highest mountain in Oregon
 Mt. Hood is a dormant or "sleeping" volcano, with steam constantly spewing from holes
at the surface
 Recent eruptions (all minor): 1804, 1853, 1854, 1859, 1865, and 1907
 Scientists believe Mt. Hood could have a significant eruption within the next 75 years
 There are 11 glaciers on Mt. Hood’s peak
 Mt. Hood is the second most climbed mountain in the world, second only to Japan’s holy
Mt. Fujiyama
 The largest party to ever climb Mt. Hood: 411 people, August 9, 1936
 In 1845, Oregon Trail pioneers Samuel K. Barlow, Joel Palmer and their parties opened
the first wagon trail over the Cascades on the south side of Mt. Hood. While still a very
difficult trail, the Barlow Trail became much preferred over the treacherous Columbia
River rafting route to Oregon City.