Inquiry-based learning is shown to improve scientific literacy (Brickman et al. 2009). Availability of cutting-edge scientific data and imagery online provides new educational opportunities to have students pursue their own scientific questions. We have created homework modules for introductory geoscience courses (physical geology and oceanography) in which students ask scientific questions, design methodologies, evaluate data, and draw conclusions using online images and datasets. Backward faded scaffolding (McNeill et al., 2009; Slater et al., 2008) supports the novice students as they learn each step of the scientific process, eventually gaining the skills necessary to carry out a full investigation independently, while still meeting typical goals of reinforcing key course concepts and of training students in broadly useful practical skills (i.e. using Excel). We assess the efficacy of these activities in improving students' scientific literacy using a modified Test of Scientific Literacy Skills (Gormally et al. 2012). Students are assessed with pre- and post-tests in the two courses across two semesters (four different instructors), and also in two biological science courses with similar populations as a control. We report preliminary results from these assessments, and we also report student perceptions of the value and transferability of the skills they are developing in the HW modules.