Primary science in Scotland has got the wind in its sails. The Scottish science education initiative, "Improving Science Education" (ISE) 5-14, has invested millions in professional development (CPD) materials and experiences for science teachers, harnessing and developing their enthusiasm for effective learning and teaching in science. Teachers have become ambassadors, mentors and trainers. They have been engaged through a number of different projects, including the successful South East Earth and Space (SEES) CPD project, managed by a consortium of organisations led by the Royal Observatory Edinburgh. This two-year project developed three workshops relating to parts of the 5-14 "Earth and Space" Scottish curriculum guidelines, and then ran five residential training programmes. Through these and other events, the project trained some 50 teachers as trainers, able to run the workshops in their local areas; and a further 350 teachers experienced the workshops for their own personal professional development. In this article, the author describes some activities and lessons learned about professional development from the SEES project.