African-American women continue to be underrepresented in science and engineering field despite years of interventions, including providing out-of-school time STEM experiences. Although some out-of-school time programs have shown impacts in participants' content knowledge and skill acquisition, impacts on science identity development have been mixed, with some research indicating that participants' struggle to access science identities developed in out-of-school time in a formal educational setting. In order to better understand the barriers to accessing and developing science identity across contexts, this study uses a combined framework of Activity Theory, communities of practice, and Critical Race Theory to compare the in-school and out-of-school time STEM experiences of African-American girls. Using data collected in both settings, activity systems for an out-of-school time STEM Club and an in-school seventh grade science classroom are reconstructed and examined for contradictions. The results indicated that objects, and therefore outcomes, of the two systems contradicted each other and tertiary tools (ideologies) from the in-school activity system created contradictions and barriers within the out-of-school time activity system. We show how the contradictions were resolved through contraction, instead of expansion, of the activity systems and how this contraction can be viewed as maintaining science (and STEM) as a property of whiteness. This work has implications for both formal and informal educators and researchers who wish to support students' science identity development across contexts and disrupt inequitable distributions of science (and STEM) resources (physical and ideological).