Upper St. Clair School District Chapter 3 Atoms: The Building Blocks of Matter student in them http://www.uscsd.k12.pa.us CHAPTER 3 student in them Upper St. Clair School District Upper St. Clair School District Upper St. Clair School District Upper St. Clair www.uscsd.k12.pa.us Upper St. Clair School District Upper St. Clair School District www.uscsd.k12.pa.us Baker Elementary School Baker Elementary School Upper St. Clair Upper Saint Clair School District Upper St. Clair School District Upper St. Clair School District Upper St. Clair School District Upper St. Clair School District