1. Constructivist learning posits that new knowledge is built upon prior knowledge and understanding develops gradually through challenging existing conceptions. 2. Conceptual change involves identifying alternative conceptions, promoting dissatisfaction with them through discrepant events, sharing the scientific conception, and providing opportunities to transfer the new conception. 3. Enhancing science understanding involves providing access to prior knowledge, organizing knowledge through graphic organizers, scaffolding learning through teacher support within students' zones of proximal development, and building learning communities through cooperative activities.