Thursday, May 21, 2015

Breaking Bolts and Exploding Glass: Thoughts on Materials Science

MatSci was, from the second week of classes, my favorite course of this semester. I was a little nervous about going into projects right away with no background first, but MatSci ended up being the best project-based class I've ever taken, and I definitely think projects were the right way to frame this course.

The Class Format
Materials Science and Biology are pretty much Olin's only two broad, introductory courses. Everything else is far more specific. The breadth of the class means it's difficult to cover all the material well. You can cover everything quickly, or you can leave out some material but get depth in some areas. The MatSci professors have decided to make the class project-based so that the depth that we get is based in something the students care about as opposed to being more tied to the professor's specialties.

We did two projects in teams of about three. The first was focused on investigating the properties of a material, and the second was related to creation or processing of a material. In class, we mostly worked on our projects in the lab, and outside of class each team read relevant chapters from the textbook and did homework problems that we chose.

This worked really well. We didn't have to wait to start doing work, but we were never doing something in the lab that we didn't understand. (Or if we were, that told us what we needed to read next, and we asked questions in the meantime.) There sometimes were no possible homework problems that were directly relevant to our projects, but we were able to find problems with the themes we needed to explore, and what we read was always helpful. I think I came out with the expected knowledge from an intro materials science course as well as a lot of experience and comfort in the lab.

During class, the professors, Rebecca and Matt, floated around the labs, checking in with all the teams, answering our questions, and training us on equipment when we were doing something new. I came out of the class knowing how to use almost all of the pieces of equipment in the lab, and I'm really comfortable using at least a handful of them. I'm not always comfortable doing lab work, so that was pretty exciting.

My Projects
In my first project, I studied the properties of three different kinds of bolts, looking at what contributed to their different strengths. We took some really cool pictures with an optical microscope, and we pulled apart all the bolts in the Instron, a machine that can apply tensile and compressive loads to objects. In that project, our focus was on properties of metals, metal processing, failure, and phase diagrams/microstructure.

My second project was on Prince Rupert's drops, drops of molten glass that are quickly cooled in an aqueous solution to form very strong bulbs that break explosively if you tweak the tail. Here we read a lot about ceramics, ceramic processing, fracture, and thermal properties. We did compressive tests to look at the strength of the bulb part of the drop, and we made the drops at different temperatures and in different solutions (water vs a potassium ion solution) to see how those factors influenced the strengths. We got a few really interesting results about strength and volatility, and we also had a cool conversation with a Wellesley chem professor at Expo about further work with a more molecular focus, which we hadn't considered. We're hoping a future MatSci team follows at least one of the directions we suggested.

From both of these projects, I have results and images that I connect with the material I learned, and that makes the subject matter a lot harder to forget. My understanding of thermal and chemical tempering is based in seeing it happen with Prince Rupert's drops (in fact, in making drops myself). I understand the difference in how ductile and brittle materials fail because of the tensile and compressive tests I did in the two projects. This is do-learn at its best.

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