I am looking for ideas for 4th/5th learning centers. I have some of my own, but there is really a minimal amount of upper elementary centers things in classroom supply catalogs. I am good at altering an idea to fit the grade, but am stuck in a few areas (mostly science and social studies, but I'll take any). I would like the centers to be more hands-on, because I think that independent "paperwork" is WAY boring for the students (and for me to grade). Anyone have some great ideas for me?