Starting a blog was pretty easy. I liked adding an Avatar. I can see the students using an Avatar to add voice to writing and to explain how something works in science.
I would use a blog to finish lessons and provide students with an open ended question. After they post, then I would ask either clarifying questions or extension questions. I think this could also be used as a PBL tool to get students to solidify their learning.
I would use the blog with teachers to help them understand science content and to share ideas.