War of the Lipids

Different ways of representing lipid structures

Chemistry has always been one of my favourite subjects, I like how logical mechanisms are, and the structures have a certain beauty - once you know what the symbols mean. I was asked to contribute some lectures on lipid analysis for the Honours Scientific Methods in Bioarchaeology course this semester. Having taught this subject previously I thought this wouldn't be a problem, and dug out my 2 hour session on lipid chemistry and nomenclature (Octadeca-cis-6-cis-9-cis-12-trienoic acid anyone?).  It's a shame I can't just start with the archaeology - Feeding Stonehenge! The Earliest Humans in North America! Mummification! There is such an exciting range of applications of the technique. It isn't until the latter part of the session however that I usually get into the archaeological aspects, as I think it's important to understand the background chemistry in order to understand how you can apply it to archaeological samples, and to understand debates over how the chemical evidence is interpreted.

Martian tripods in disguise

Which has been fine in the past, as the classes I have taught have been specifically for archaeological science students with backgrounds in biology, chemistry etc. However it turns out that the students on this course come largely from non-science backgrounds, and are relatively new even to concepts such as isotopes. I had a bit of a panic at this point, the thought of being faced with that nightmare situation where you can see faces glazing over and switching off while trying in vain to explain that lipid analysis in archaeology is actually really useful, and not that hard, honest. Which I think is true, but perhaps my approach to teaching it needs to be adapated for students who have probably not done A Level/Higher chemistry. I don't want to put everyone off at the first slide. I admit it, you might indeed look at this slide (above) and wonder what on earth all those spherical blobs are, and yikes do I really have to remember all of those letters and names? So how best to help students remember the basic structure? Then it came to me - don't they look just a little bit like the tripods from War of the Worlds? So now my lecture refers to fatty acid legs (saturated fats = straight legs, unsaturated fats = bent legs), and glycerol heads. More complex lipids such as sterols have leg upgrades. I'm hoping this will work really well and I'll have lightbulb moments instead of glazed faces...or it could all go horrible wrong and I'll end up with exam answers discussing how tiny Martian invasion machines are responsible for the origins of dairying.