All praise and thanks are to Allah. I dedicate this work to my mom, my dad, my wife Dawn, and to the students in 8 th and 9 th grades in Lebanon. You all helped me make my dream comes true. v ACKNOWLEDGMENTS First of all, I thank Allah for helping me achieve this work. I am especially grateful to my advisor, Dr. Wasim Maziak, for all his support. He is a wonderful person, a caring advisor, and I learned a lot from him. His support throughout this journey was outstanding. I want to thank my parents for their love and support, my lovely wife Dawn, as she shines my life and for her patience and support during this long journey. I also