Nature of Science FPLC Kraft 2005-6

From CTLpedia

Reflections on my Experience in the Nature of Science Faculty and Professional Learning Community, Kaatje Kraft, Physical Science Department, Mesa Community College, Contact me (mailto:k.kraft@mail.mc.maricopa.edu)

Summary: I wanted to know more about the Nature of Science and what that means to students in my geology classes.

Basic Reflection on How Science is done in the field of Geology

What is the nature of science to you, and how do you teach it in your discipline?

Geology is a science that works on time frames that are typically well beyond our life spans. This poses a challenge when it comes to being able to observe the science "in the making." As a result, a guiding principle for much of what we do is the principle of Uniformitarianism (the present is the key to the past). We observe what we see today to help us understand what happened in the past. This is a fundamental to geology. However, there are also occasions that we recognize to be extremely rare events that may or may not have occurred with us to observe the actual process (e.g., meteor impacts). Modelling is a key component to understanding all of these processes.

As I teach my students, I try to impress upon them the importance of this principle and use it as a constant tool in interpreting the past. The challenge of helping them to better understand the depth of time on Earth is one of my greatest challenges.

How do I think about how I teach the NOS for geology?

Depends on the day...there are some days that I feel like I've really impressed upon them how geology is done (typically when it's a more authentic activity, like providing them with data from an active volcano, or have them interpret data and realize the uncertainty associated with it).

There are other days where I struggle, how do I communicate with them if they can't "speak the language?" How do I avoid just dumping a bunch of terms in their lap, but still allow them to understand the concepts?

What Terminology do I use and how do I use it?

In terms of NOS terminology, I do use hypothesis in conjunction with postulate and theory. Law is almost never used in my class.

An example from just the other day was when we were discussing the Theory of Plate Tectonics. I had students examine the different lines of evidence that worked toward the development of the theory. I discussed how not just one line of evidence supported the theory, but that all of these different postulates worked together to support the theory.

How is data collection done in my discipline?

Most data collection is done by observation which leads to interpretation.

Several examples from a recent field trip to the Grand Canyon include:

In the Coconino Sandstone, there are cross-beds from the depositional environment (by watching deposition of present-day sand dunes, we can see how they deposit in order to preserve this texture) during the Permian (approx. 250 Ma). I had students measuring the ancient depositional surfaces of these dunes and plot them on a rose diagram to determine if there was one or more directions to these ancient sand dunes.

In the Toroweap Formation, there are several different members (smaller units within the bigger unit) with varying properties. Students worked to determine the thickness of the layer as a whole, but also look at the rocks and how they changed to determine what members were present and how thick they were for that given formation. As a result, they were able to defend what members were present based on their observations of rock types present. A more advanced portion of this would be to then determine what the paleoenvironments are for those rock types based on what sediments/chemicals we see in today's environment.

The following day, we hike into an old volcano and make interpretations about the properties of the volcano. These are based on the minerals observed, the weathering pattern, the types of rocks present. Again, applying the principals of what we see today to interpret the past.

Because geology is so dependent upon human observation, which can easily be manipulated to fit an idea, we commonly work on the notion that there should be multiple working hypotheses when entering a field area and encountering an intruguing outcrop. This way we hope to avoid the, "I never would have seen it if I hadn't believed it" mentality/accusations.

What am I doing in my classroom to promote the understanding of NOS for my discipline?

I try to have them examine data and make interpretations from that data. It's difficult, because so much of what we do is field based, the challenge is to try to bring the field to the classroom as much as possible.

For example, I had students look at cross-sections from an area near the Chicxilub Impact site in the Yucatan Peninsula that some propose is the site that marks the Cretaceous-Tertiary Boundary (the great dino extinction). Recently, others argue that this impact occured several millions of years before the K-T boundary. After explaning some basic principles and the general argument, I asked them to take a side and provide evidence to support it. The nice thing about the cross-sections were that different cross-sections provided arguments for both sides. So there were differences of opinion. We discussed what other evidence they might want to then investigate to determine that further (my real goal is to work so that that CAN be the next step they take, I'm working to get there).

In my geologic disasters class, there can be more real time data because these events happen on a more human time scale. As a result, we're able to look at gas/seismic/& GPS data to make predictions about the likelihood of this volcano erupting. It also leads into discussions about how that will influence the local population (One of my common messages for that class is that science does not occur in a vaccuum, and can easily be affected by outside influences, culture, politics, warfare, poverty, etc...)

How would I do research in my specific field (is that different or the same as to how you teach it in your classroom)?

Research typically includes a field component--going out and researching an area. This involves some aspect of mapping, identifying rocks, taking samples back to the lab to analyze them (either with microscopic work, or other instrumentation like mass spectrometer). For my masters I mapped an asbestos deposit to determine how it was exposed relative to the topography. I analyzed the stable isotope content to determine the temperature of formation for this system. Modelling is also an important component. For example, as my husband is working on his PhD, he has collected samples and looked at them under different microscopes (SEM, TEM, etc...) and then tried to model what he thinks might be happening in nature to try and replicate what he sees with his lab samples.

It's very difficult to be able to get all students outside to do any authentic research. It can happen in small "pods" but not as a class whole. As a result, most of my teaching is providing them data already taken and then figuring out how to interpret that data. Which is unfortunate, because what makes this discipline so much fun is when you see it in context. I think it is very difficult for students to visualize some of these big ideas without seeing them on a larger scale. It's also frustrating, because they don't necessarily appreciate how science builds on ideas already out there and well accepted. I also think that there are few opportunities for student to really understand the modelling process. Which also leads to a lack of understanding about how science can be done.