Israeli junior high-school science teachers usually have a background in biology, and their knowledge of physics is limited. We show that by improving teachers' "qualitative understanding" it is possible to increase their confidence and willingness to teach physics. We conducted three-day workshops for teachers (n = 92), which were followed by ongoing activities and support. The teacher workshops were based on a new qualitative approach that we developed for studying mechanics, which has been shown to be effective with students. A study of teachers who had not participated in the workshop shows that they had the same conceptual difficulties as their students. A comparison of pre- and post-workshop questionnaires indicates that the participating teachers gained self-confidence in their ability to explain everyday phenomena, changed their views about the relevance and interest of physics to the students and were willing to implement the method in their classes. (Contains 5 tables and 2 figures.)