Teaching Science by Analogy: How to “Grab” the Non-Major

“I’m bad at science.”

“I hate science.”

“I don’t get science.”
These are three phrases I hear regularly on the first day of classes. At Champlain College, where I am a full-time faculty member, we do not have science majors, so I teach science-based courses entirely to non-major audiences. These students are in my course because there is a general laboratory science requirement that must be fulfilled to graduate.

Many of my students are generally unhappy about the science laboratory course requirement and enter my classroom with an attitude that often reflects their feelings. This presents me with a unique challenge: how do I capture these students’ attention and show them that science is not what they think it is? How do I show them that they are not bad at science, they can “get” science, and they don’t need to hate science?

attentionOne of the techniques I have employed in my classroom centers around the idea of taking away the fear of understanding the “technical” nature of science by teaching scientific concepts and knowledge through the use of analogies. I try to use analogies relevant to students’ everyday lives, no matter how ridiculous the comparison might be.

As an example, I use an analogy to explain the difference between saturated and unsaturated fatty acids. In prior class sessions, we have discussed single and double covalent bonds. I have already introduced the idea that a double bond changes the geometry of the molecule in which it is located, which will affect the three-dimensional structure of the molecule. I then ask the students if they have heard about saturated and unsaturated fats. Most have, and most even know that unsaturated is the “better” type of fat. Not one of them ever knows the difference between them, however.

This is when I dive into one of my food analogies, which is a favorite way of mine to anchor scientific information to something they already know. I liken the saturated fat to skinny pretzel rods. These items are pretty linear in shape, and if you have a small plastic snack bag, you can cram quite a few pretzel rods into the bag for a good-sized snack. (You can even bring the food items to class for demonstration if you like). I then explain that this is the equivalent to saturated fats; the complete lack of double bonds in the fatty acid tails makes the molecules pretty linear and easier to pack into tight spaces, and that this usually results in these types of fats being solid at room temperature.

Then we talk about unsaturated fats, and how they have at least one double bond in the fatty acid tails. I usually use this as a way to discuss what a monounsaturated fat is versus a polyunsaturated fat and how those prefixes of “mono” and “poly” help you know how many double bonds are in the fatty acid tails. I remind them that the double bonds introduce bends or kinks into the molecules, which causes them to have bends in their structure. I liken these molecules to the shape of cheese curls – those puffy, curved, construction zone-orange salt bombs that are a personal favorite.  I then ask the students to compare how many cheese curls you can fit in the same size plastic snack bag as the pretzel rods, and they immediately realize you can’t put nearly as many cheese curls in that bag as you can thin pretzel rods.

We then discuss how the bends in the cheese curls prevent tight packing of the food, as the double bonds do in unsaturated fats.  This results in more room in between molecules, which gives these types of fat the property of usually being liquid at room temperature. You can almost see the light bulbs going off in students’ heads. They begin to understand on a very basic level not only what the double bond does to the shape of a molecule, but also why there is a difference between saturated and unsaturated fats and why one is liquid and one is solid.

After using an analogy like this in one of my Introduction to Human Biology courses, a senior Business major who had made it crystal clear to me that he was only in class to check off his Science requirement to graduate looked at me and said, “I don’t know, Dr. K. You are making science seem so easy.” I think I floated through the rest of my day.

Now, you may take issue with my analogy. After all, thin pretzel rods and cheese curls are much different in diameter, they aren’t made of the same material, and the analogy isn’t really any good if you are trying to accurately compare the structures of saturated versus unsaturated fats. My response: you are absolutely correct, but try it anyway!

As scientists we are trained to be detail-oriented and accurate. How could I ever use such an inaccurate analogy? The answer is simple: particularly for the non-major, it’s not about that. It’s about getting the “big picture” across, just like the “big idea” you would use in Backward Design (1). Teach them accuracy and how to be detail-oriented in lab. There can be a big difference between 1.0 and 1.5 mLs when running an experiment. If you try to find perfect analogies for concepts in science, you will find very few. So don’t avoid them. Be crazy. Be a little inaccurate. But help the students understand and remember by showing them that they ALREADY understand the concept. They just need to apply their knowledge in a different way. Your students will “get it”, even if they don’t thank you. And you just might to get to indulge in some cheese curls.

 

Reference:

  1. Wiggins GP, McTighe J. Understanding by design. Alexandria, VA: Association for Supervision and Curriculum Development, 2005.

 


PECOP Seiler
 

 

 

Kathy Seiler is a full-time Assistant Professor of Science and Science Coordinator at Champlain College in Burlington, Vermont. She goes by “Dr. K” on campus and subjects her students to blues and jazz music during labs. When she isn’t in a lab or at her desk, she can often be found in a classroom trying to recreate the movement of cilia, flagella, and the general function of ribosomes through body movement and silly sound effects.

 

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