How to supervise an undergraduate student if I am a PhD student coming from a different field? I have joined a new research group as a PhD student about one month before. Few days ago my supervisor told me I should supervise an undergraduate student for a research project. However, the things this research group doing are totally new to me. When I had discussions with the undergraduate, I sometimes find he knows more about me in the project. I find embarrassed, and don't know how to supervise him when I can't quite understand his project. 

I know as a PhD student, learning new things is essential (and I enjoy a lots). However, I do not have the time now. The undergraduate needs to have some results in few weeks for some sorts of mid-term review report. I agree to supervise him because I don't want to reject my supervisor, I just join the group and it seems inappropriate to turn down. 

What should I do in this situation? I don't know if it is common for a fresh PhD student to supervise undergraduates even you are coming from a different field. Of course, I am doing a lot of reading for this, trying to beef my background knowledge up.
The situation may be challenging, but you don't need to be uncomfortable with it. In academic research, it is not uncommon that the one doing the actual project is more familiar with the material than the one supervising it. While it's probably rarely the case in an undergraduate - PhD student relation, it almost becomes the norm in the PhD student - professor relation, at least as the PhD student becomes more senior. Keep in mind that supervising is not only about teaching the material, but also about how to act and conduct research professionally. I hope you feel more confident about the latter aspect!

In your specific situation, there seem to be two possible steps if you feel you need to do something about it.


Talk to the student you supervise, explain that your background is in a different field, and openly state that you may not be able to fully help on the content side of the project. If the student is sufficiently confident in working more independently, you should be able to be more relaxed as well.
Otherwise, you may need to talk to your supervisor again and explain the problem. Maybe he can point out an additional member of the group who would be able to help with the aspects you can't cover.