Plate choctonics, part 2

Well, having suggested Creme Eggs might be used as analogue Earths in an introductory geology class, it turns out I wasn't too far from the truth.

We used Mars bars.

Mars does have tectonism after all

One set were chilled, the other kept at room temperature, and the students were then asked to apply stress to them.  The idea was to observe brittle failure in the chocolate (and to a slightly lesser degree, the nougat) and ductile failure in the caramel.  Broadly, this mimics the behaviour of different rock types, such as interbedded sandstones and mudstones (you can kind of see what I mean in this photo).

Under colder conditions though, the caramel also broke brittly, demonstrating the importance of temperature in the type of strain.  The students were also asked to examine the speed of deformation, by comparing what happened when a cold Mars bar was squashed rapidly with one squashed slowly.

For amusement, we then added some Snickers bars to the mix.  The peanut-rich layer serves as a rather nice imitation till or conglomerate, showing how compositional variation also plays a role.

And then we got to eat all our experimental materials, which is not something you can often do in a geology class (unless you like a bit of geophagy, of course).

[Next time - why a replica volcano made with Softmints and Lemonade is not as good as one made with Diet Coke and Mentos]