PhD position interview: How specific should my idea of the topic be? I just finished my master in Geophysics with some help from here ;). Now I applied for several PhD positions in Natural Sciences and just got an invitation for a personal interview for one of them. 

The topic of the position is described in the call but over all it seems very general to me (I really have no experience if that is common for PhD positions).
During the interview I’m supposed to give a 10-15 min oral talk about "specific research questions and methodologies" I suggest to focus on and about "results of a first paper". 

I have some experience in one of the methods mentioned in the call and could probably come up with a quite elaborated idea for a paper (though I would have no idea if everything or anything would work the way I propose it, never having worked on a paper) 

My understanding is hat even older scientists need time and work in a topic to figure out what exactly there paper will be about. So probably I should just kind of suggest a focus topic within the broad framework of the topics covered in the call?

I guess my main question is: How specific should I really be?
(because I should obviously try to avoid boring my interviewer by only repeating part oft he call)

I should probably also mention that I have only three days to prepare.
The way I interpret the topic you were asked to present on is that they want you to present on some work you have complete such as your first paper (or possibly a masters thesis if you have not published anything).

The idea of this is probably to get an idea of how you think/do research and provide a nice introduction into finding out what your interested in.

From your question it sounds like you think they are asking for something else. Now I could be entirely misunderstanding what is asked for (I just have your question), but if you are unsure I would suggest you send a polite email to clarify what the talk should cover.

For what you should say in the talk I would try and answer these questions:


What was the motivation for the research (why is it interesting)?
What did you do?
What are your results/what do they show?
Why are the results significant/interesting?