Issertation topic in Science Education, PhD

I am looking to choose a topic for my dissertation in PhD in Science Education and I wrote this title as first draft:
SCIENCE EDUCATION INTERNSHIP FOR PROFESSIONAL DEVELOPMENT OF PRE-SERVICES TEACHER: AFFORDANCES AND CONSTRAINTS.”
BUT,my adviser said that this topic is so broad and now, I need your help for making this title so interesting and more focus and then make a research in some Journals in science education about the internship practicum or training, just I need to find out what was the big issue about this topic and has been done.
Please write a brief about the big issue to help me out for the dissertation topic and then the big question for my research!!

these are the most Journals I have to take a look on it about this topic :
1NARST
2ASTE
Please see the attachment file.