The CoMPASS project integrates two modes of learning science: digital linked text in a hypertext system, CoMPASS, and accompanying design challenges. Several CoMPASS units have been developed covering a range of topics in mechanics and enable students to learn about key concepts such as work, energy, force, acceleration, mechanical advantage etc. The principle guiding the design of CoMPASS materials is to enable students to see relationships between concepts and principles. Concept maps that change dynamically based on the concepts selected by students, supplementing the text in the CoMPASS system, help students to see these relationships. The design challenges provide students with a context for their hands-on science investigations, and enable them to see the interconnections between the concepts (e.g., force and distance).