These are a few Valentine's day science projects that can be done with a wide variety of age groups. I have included some suggestions for making them appropriate for the middle school grade levels as most are written for elementary grade levels. I have done all of these projects with my seventh grade students and they have enjoyed them. They are quick projects that can be completed within a class period. There are 4 projects: Changing color carnations (a short lab), Crystal hearts (another short lab), Healthy Hearts (includes 2 small research activities and one lab), and a candy lab.