Science, Technology, Engineering, and Mathematics (STEM) education curriculum is designed to strengthen students' science and math achievement through project based learning activities. As part of a STEM initiative, SeaPerch was developed at Massachusetts Institute of Technology. SeaPerch is an innovative underwater robotics program that instructs students in how to build an underwater Remotely Operated Vehicle (ROV) following a STEM curriculum, including spatial thinking and rotation ability. This research study investigated if the students' SeaPerch program and its spatial experience and training gave the opportunity to develop strategies not only in manipulating three dimensional objects but in strengthening mathematical ability (e.g. spatial thinking) in elementary, middle, and high school students with specific focus on gender and age. This research study sample consisted of two groups of students: one that participated in the after-school SeaPerch program and the other that did not participate in the after-school SeaPerch program for the 2011-2012 school year. Both groups comprised students in similar grade levels and the MRT preassessment scores. To measure students' spatial rotation, the researcher used the Vandenberg and Kuse Mental Rotation Test (MRT). An independent samples t test was conducted to determine the effect of the SeaPerch program on MRT scores. The SeaPerch students (M = 1.35, SD = 2.21) scored significantly higher gains than the Non-SeaPerch students ( M = -0.03, SD = 1.72), t (737) = 8.27, p = <0.001. The effect size as measured by Cohen's d = 0.697, indicated a medium practical significance. At each school level, MRT post assessment scores for students in the SeaPerch program increased significantly more than scores for students in the non-SeaPerch program. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]