Using Analogies to Teach in the Geosciences

Teachers often use analogies when describing complicated new material to their students. Sometimes they are not even aware that they are using analogies because they do it automatically. Whenever an explanation begins with "it's just like..." or "it's similar to..." or "think of it this way..." an analogy is being used to explain a new concept to students. Not only can they be helpful for teaching novice students new science concepts, but they have also been suggested to be fundamental to the development of new scientific ideas. Some researchers even argue that analogies are the "lifeblood...of human thinking," (Hofstader, 2001). The role of analogy in developing new scientific ideas is thread that runs through the history of science, including the development of the heat engine by Sadi Carnot and the idea of local motion by Robert Boyle (Gentner & Jeziorski, 1990).

Analogy refers to a comparison between two examples that is typically based on their structure or function. The purpose of an analogy is to help explain or clarify difficult-to-understand concepts. Analogies are often used in the sciences because they can be especially useful for understanding processes or phenomena that are difficult to perceive (Jaeger, Taylor, & Wiley, 2016; Orgill & Bodner, 2004). Although the concrete features of the examples may be similar or dissimilar, analogical comparisons are more concerned with how the features relate to one another. That is, the essence of an analogical comparison is finding the structural alignments. For example, a common analogy in the geosciences is using the example of a layered cake to describe stratigraphic layers. In this analogy, the cake and the earth have some very different features, but they are in correspondence because they are both made up of layers of different materials. What makes this analogy especially useful is that the base (the layer cake) is very familiar to students and easy to visualize, whereas the target (stratigraphic layers in the earth) is novel and very difficult to visualize.

Despite the fact that analogies offer many opportunities for the development of rich mental models and scientific insights, they do come with their own set of challenges and potential pitfalls that educators should be aware of. First, although analogies are frequently encountered in everyday life, it is not appropriate to assume that students will necessarily understand how they work. Therefore, students should be taught what analogies are, what they are used for, and what their disadvantages may be (Brown & Salter, 2010). Second, it is important that students understand all of the elements of an analogy so they are able to decide what is intended by it. One of the biggest risks in using analogies in science is that a student may be left with an ill-defined idea of the new concept or even an incorrect or misconceived idea. Because all analogies have misalignments between the base and the target, misconceptions can arise if the mappings between the base and the target are not clearly explained. However, deep learning about the concepts at hand, and even more generally about the nature of science, can be achieved by explaining the limitations of an analogical example. Finally, it is important that the analogies teachers use are "good" analogies. Specifically, the most effective analogies are simple, easy to remember, and based on familiar concepts.

While analogy is useful across many learning domains, it is particularly central in geoscience learning because many of the important geological processes occur over ranges of space and time that cannot be directly perceived by learners. There are many examples of analogies that have been used in geosciences textbooks and labs that cover a range of important concepts. In order to increase the use of analogy in geoscience instruction, it may be helpful for geoscience educators and researchers to create a database of important, yet difficult-to-learn concepts and analogical examples that may be beneficial for teaching these concepts. By putting together such a database, instructors may be more likely to use analogies in the classroom and they may be able to use them more effectively, for example, when a particular student is struggling to understand something. Aside from being a convenient resource for educators, this repository of analogical examples could serve the research community as well. Education researchers could work alongside Geoscience educators to empirically test the effectiveness of these analogies, determine the optimal instructional supports that are required when using the analogies, and determine for whom analogies may be particularly useful.

As a member of the Geoscience Education Research community, I invite anyone reading this blog to comment and add any analogies that have been useful to you in your teaching experiences! I have gotten the list going with some examples below:

Analogies from the geosciences

• Continental masses -> a buoy floating on water; icebergs in the ocean
• How rocks obtain a paleomagnetic signal -> compass needle: some minerals (magnetite) act as small compass needles that get locked into position as the rock cools.
• bonus: if students are unfamiliar with compasses, they can have a hands-on experience with them in the lab
• Great Lake Missoula Floods during the last Ice Age -> the glacier was like a glass of water holding Glacial Lake Missoula. When the glass tipped, the lake spilled out over the land.
• Great Lake Missoula Floods during the last Ice Age -> the glacier was like a dam holding back Glacial Lake Missoula. When the dam abruptly bust, the lake spilled out over the land.
• Stratigraphy -> layer cakes with different colors of icing
• Understanding the amount of useable soil on Earth -> peeling an orange
• Convection of the mantle where Earth's core provides the heat -> simmering pot of water where the burner provides the heat
• Layers of the Earth -> An apple
• The mantle ->hot wax or silly putty
• Gas exsolution during an earthquake -> shaking a bottle of Coke
• Stagnant lid tectonics -> the blowing off of a top on a pot of boiling water

Physical Models as Analogs

• Folding/bending/tearing a sheet of paper -> Ductile or brittle deformation of rocks
• Lava lamps -> density/temperature controlled buoyancy
• Clay and play doh -> geological layers, sedimentological principles
• Sandbox models -> faulting and folding
• Flumes -> Fluid and sediment mechanics
• Dry Spaghetti noodles -> asperities on a strike-slip fault

References

Brown, S., & Salter, S. (2010). Analogies in science and science teaching. Advances in Physiology Education, 34, 167-169.

Gentner, D., & Jeziorski, M. (1990). Historical Shifts in the Use of Analogy in Science. Technical Report No. 498.

Hofstadter, D. R. (2001). Analogy as the core of cognition. The analogical mind: Perspectives from cognitive science, 499-538.

Jaeger, A. J., Taylor, A. R., & Wiley, J. (2016). When, and for whom, analogies help: The role of spatial skills and interleaved presentation. Journal of Educational Psychology, 108, 1121-1139.

Orgill, M., & Bodner, G. (2004). What research tells us about using analogies to teach chemistry. Chemistry Education Research and Practice, 5, 15-32.