Trilobites Live! part of Dilemmas
I teach Historical Geology at a large public university. As I was setting up class the other day, a student, Eric, nervously approached me and asked a question that caught me off-guard. "How do you know for sure that trilobites and humans didn't co-exist?" he asked. I smiled, thinking he was making a joke. After all, we were several weeks into a second-semester geology course and this was the first time he had expressed these ideas. "Nice one," I said, "how can I really help you today?" But then I realized he wasn't trying to be funny. His face turned stoic and serious, but before I could gather myself and formulate an answer, he continued, "You throw around these huge numbers for the age of the earth, the age of the rocks and the age of the fossils. But how do you know? Aren't you just repeating the numbers that you have read elsewhere? In a church group, we learned that humans and all other life were created at the same time, only a few thousand years ago."

Too Cool for Science part of Dilemmas
On a frigid Minnesota afternoon, I had just finished a mini-lecture in my introductory class, and I threw out a question to the whole class. Chris responded enthusiastically with a wonderful and correct contribution. At which point, Sam groaned and said, in a voice audible to the entire class,"suck up!" A few other eyes rolled, and other hands that had been raised were slowly lowered.

Irrecoverable Failure part of Dilemmas
The course is an Earth Science for Teachers course. The content is outlined in a popular 16-chapter introductory text. Licensing for teachers specifies a certain block of content to be covered, which is about 12 of the 16 chapters. The professor gave two high-stakes (counted for grade) quizzes to prepare students for their first test, over four chapters, which is an essay exam. Quiz grades were low, so the teacher chastised the class about being unmotivated and urged them to study more.

Meeting learning goals with a below average course part of Dilemmas
During the fall 2006 semester I taught a first year writing seminar entitled "The World's Oceans in the Global Environment," a course designed to introduce students to important topics in marine science in the context of Earth systems science, as well as key issues in ocean policy (e.g., fisheries, implementation of marine protected areas, etc.). As a writing seminar, most student work during the semester was in the form of writing assignments.

Scientific uncertainty and global warming part of Dilemmas
Climate change is the major environmental issue facing all inhabitants of spaceship Earth. As Earth science educators, we must inform students about the scientific consensus on global warming and projections of future warming through this century. Recent research has resulted in a dramatic advance in our understanding of climate history.

Empathy part of Dilemmas
Students in a small upper level class discussing global warming students argue that anything we do to "save" the environment is worth any cost and ultimately benefits everyone equally. We explain that a person in another country might be willing to accept a degraded environment in exchange for economic improvement. Students are willing to accept that as an intellectual argument but it becomes clear in subsequent discussions that they did not change their arguments to accommodate this idea.

Fixation on grades part of Dilemmas
Each semester our university offers several large-enrollment (n ~ 220) sections of a lecture-based introductory physical geology course. Although the course can be counted toward a geological sciences major, it functions mostly as a service course that provides non-major students a science credit necessary for graduation.

"I Want to Believe You": Is there comfort in simplicity and discomfort from complexity? part of Dilemmas
Professor Spurrier has prepared carefully for a presentation on paleoclimates, in an effort to have students learn about past climate changes. She presents information on current and historical measurements, tree ring data, ice core data, and ocean sediment data, going further into the past and demonstrating the inferences on what the climates were like. The students seem restless with this presentation, and finally one bright student raises his hand.

Al's bandwagon part of Dilemmas
In the eight person seminar class is an inquisitive, nontraditional, student who is a motivated popular science reader. This student challenges the conclusions made by the vocal majority of scientists that global warming is caused by human activity.

Sermon of the rocks part of Dilemmas
Professor Jones has taught in the geology department for 30 years. His notions of teaching and learning can be summarized in the saying, "I'm here to teach, and students are here to learn." His approach to teaching involves lecturing from the textbook that he authored. Lectures, for Dr. Jones, are not unlike a Sunday sermon. He talks and some students listen. Others sleep, read newspapers, and surf the Web. Student evaluation of his classes and teaching effectiveness are routinely low.