One of the biggest surprises of my fledgling academic career is how much I've come to enjoy teaching. Helping students to understand a difficult concept, or seeing their imagination gripped by a new idea, is immensely rewarding. But right now, indulging this passion is not without its dangers. I had a chance to ponder the conflicting risks and rewards during two weeks that I spent out in the field with my Johannesburg students, looking at some of the oldest rocks on the planet.

I enjoyed myself, and because good knowledge of the material is necessary to teach other people properly, I learnt a lot myself about what ancient lavas and sediments — the subjects of our study — could tell us about Earth 3.5 billion years ago.

On the other hand, it could be argued that the short-term nature of my position here means I can ill afford to spend time away from my research. Involving myself in teaching is 'good experience' to put on my CV, but counts for nothing without more tangible qualifications such as a good publication record.

It seems like a bit of a paradox. But to give myself the best chance of getting a teaching position in the future, I may have to ration how much teaching I actually do in the present.