The current study compared different learners' static and dynamic mental images of unseen scientific species and processes in relation to their spatial ability. Learners were classified into verbal, visual and schematic. Dynamic images were classified into: appearing/disappearing, linear-movement, and rotation. Two types of scientific entities and their related processes were investigated: astronomical and microscopic. The sample included 79 female students from Grades 9 and 10. For the purpose of the study, three instruments were used. The Mental Images by Guided Imagery instrument was designed to investigate participants' visualization of static and dynamic mental images. The Water-Level Task was adopted to estimate participants' spatial ability. The Learning Styles Inventory was used to classify participants into verbal, visual and schematic learners. The research findings suggest that schematic learners outperformed verbal and visual learners in their spatial ability. They also outperformed them in their vividness of microscopic images; both micro-static and micro-dynamic images; especially in the case of appearing/disappearing images. The differences were not significant in the case of astronomical images. The results also indicate that appearing/disappearing images received the least vividness scores for all three types of learners. (Contains 6 tables and 4 figures.)