Chemicals in My Food

John Coupland is a Professor of Food Science at Penn State. His research program is on the physical properties of foods, in particular fats and oils. He teaches undergraduate Food Chemistry and graduate level Food Chemistry and Food Physical Chemistry. This is about that.

Posts tagged FDSC400

Dec 29

Using a Wiki in an Undergraduate Class

Every fall I teach an undergraduate course in Food Chemistry to about fifty students, mainly juniors in Food Science. Three hours of lecture, three hours of lab, exams, homework, reports, C-minimum to graduate. Food Chemistry is taught in relatively few universities so there is no real commercial pressure to produce a student-friendly textbook and instead I depend an interactive lecture as my main method to deliver the information they need.

Students seem happy enough about this approach (perhaps only because I don’t ask them to by a hundred dollars’ worth of books) provided they can have a copy of my PowerPoint slides in advance. I hate this. My slides provide a rough map of my class rather than a detailed list of the points (however powerful) I need them to know. Indeed I am suspicious of isolated facts in the context of science education; without a framework, learning facts is like learning poetry in a language you don’t know. I try to frame most of my lectures as series of thought experiments that try to engage the class in a series of linked “why” and “what next” questions. I need them to be engaged in thinking about the argument I am trying to build rather than trying to write down every word I say. Consequently many students, poorly trained in note taking to begin with, end up with a minimal written record from my lecture, no textbook, and nothing to study for before the exams.

Last semester I experimented with a private class Wiki as a way of allowing students to collaborate in note taking. I used a fairly simple, linear structure with one page per lecture. I added a skeleton of six or seven top-level headings for each class and allowed students to add whatever they wanted. Students could choose to be anonymous to their peers but I needed to know who they were so I could award a small amount of extra credit for participation. I did my best to edit as the material developed but I had a disclaimer that I couldn’t guarantee the material was ever “correct”. A few observations on the results:

  •  The Wiki program selected (Wikispaces.com) was very intuitive and no one requested assistance in using it.  However, only about 20% of the class ever made an edit to the Wiki and I depended on 3-4 students for most of the work. This seems consistent with the typical contributor:lurker ratio in most online communities.
  • Even the students who didn’t contribute found the Wiki helpful.  In a mid-semester survey (~50% response rate) 100% of the respondents saw some or a lot of value to the Wiki and wanted to see it continue. In the end-of-semester course evaluation many students identified the Wiki as a highlight of the course.
  • Students spontaneously used the discussion feature for questions and answers. I did most of the answering but the public nature of the process had a general benefit. Students rarely edited one another’s contributions.
  • The structure I created remained intact as the Wiki evolved and there was little effort to generate links between topics.  This was clearly a class Wiki, focused and shaped by the form and content of my lectures. It had value to students taking the class but probably not to a wider audience.
  • The document produced served as a robust set of notes for my class and was better than an individual student could have created.  There were some mistakes but the final quality was remarkably good.  I was confident a student could use the Wiki during exam preparation.

I was pleased with the results and I would recommend a Wiki to other instructors working without an appropriate textbook.  I suspect without a higher participation rate you would need a minimum of 50 students to maintain momentum.  I will use a similar approach in the future and I will probably begin again from scratch as I think the process of generating the Wiki has value to the students who participate.  Indeed I will use stronger incentives to encourage all students to get actively involved in writing and in particular editing.   


Sep 19

Glass transitions in candy


Sep 18

How to make a plot of larger data sets using Excel


 

How to draw a scatter plot of scientific data in Excel


A short video demonstration on how to use Excel to do simple scientific calculations. 


A short video demonstration on how to format a simple table of scientific data. 


Jun 29

A simple model for globular proteins as nanoscale particles with hydrophillic surfaces and hydrophobic cores.  Helpful to understand the use of proteins to  modify food structure (e.g., egg white gels, tofu).


Oct 1

A simple picture of fluid flow and viscosity.  Discussion of how adding particles to the liquid increase the viscosity.  Particle aggregation increases the viscosity further and can even lead to gelation.  Useful to understand many liquid to solid transitions in foods (e.g., yogurt, cheese curd, tofu)


Sep 2

Water migration between two components in the same food is driven by differences in water activity not differences in water content. 


Aug 25

A simple model of an intermolecular bond as the sum of an electrostatic attraction at long ranges and a steric repulsion at a shorter range.  The bonds are weak and fairly short range, typically only nearest-neighbor.  The changes in the number and type of bonds is critical to understanding how molecules organize themselves against the randomizing effects of entropy.