We developed new computational tools that allowed children to create their own scientific instruments�enabling today's children, like scientists of earlier eras, to become engaged in scientific inquiry not only through observing and measuring, but also through designing and building. We found that when students build their own scientific instruments, they not only become more motivated in science activities, but also develop critical capacities in evaluating scientific measurements and knowledge, make stronger connections to the scientific concepts underlying their investigations, and develop deeper understandings of the relationship between science and technology.