Milky Way - Ductile and Brittle Demo
Mark F. Wood
Jefferson Community and Technical College (JCTC)
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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
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- Alignment of Learning Goals, Activities, and Assessments
- Pedagogic Effectiveness
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This page first made public: Jul 7, 2008
Used this activity? Share your experiences and modifications
Milky way candy bar is given to each student. They are told to bend it and write down what they observe. The activity takes an every day object and ties the geologic terms to something they have experience with.
Introductory Physical Geology (majors or non-majors), Structural Geology
Skills and concepts that students must have mastered
No mastery is skills is needed; I give a lead-in discussion of ductile
and brittle behavior. I link it to the stress / strain graph and after
we discuss what happens and how it relates to the chart, what is
ductile behavior and what is brittle, where the elastic limit is found
and when we exceed the limit and what happens. This is then related to
How the activity is situated in the course
This is part of a sequence of exercises and demonstrations in my
introduction to structural geology, the earth, and rock deformation. It
is all tied to the stress / strain graphing of brittle and ductile
behavior. This leads into structural geology, folds, faults and greater
plate tectonics and mountain building discussions.
Content/concepts goals for this activity
The goal is to be able to better relate to the meaning of the graph and what stress and strain are. I find that relating rock behaviors to every day items help students to visualize and conceptualize the more complex ideas.
Higher order thinking skills goals for this activity
This is pretty basic stuff I work on in my class.
Other skills goals for this activity
I have tried to do this in groups as well and it works quite well.
Description of the activity/assignment
To prepare for this activity the students are to have read the chapter
in the book relating to rock deformation. We have discussed
metamorphism and have used a couple of other related demos. I relate
ductile deformation to bending clay or a coat hanger and brittle to
breaking a pencil or a plastic rod. I graph these on the black board
and we discuss what might happen if we mixed materials or changed the
temperature. I then break out the Milky Way bars and pass them out.
They are to bend them in half and write down what they observe.
Sometimes I break into groups to discuss if there is time otherwise we
go over the behavior and pass in the assignment.
Determining whether students have met the goals
I determine the effectiveness of the assignment in several ways. First
I note which students participate in the discussion and at what level
(I grade daily discussion). Also I grade the work they hand in. I have
several quiz and test questions directly and indirectly related to the
activity.More information about assessment tools and techniques.
Download teaching materials and tips
I learned part of this from my structural geology prof. Dr. Eric Frost
currently at Santa Barbara. I've never seen another reference to it.