In science, technology, engineering, and mathematics (STEM) education in pre-college, engineering is not the silent "e" anymore. There is an accelerated interest in teaching engineering in all grade levels. Structured engineering programs are emerging in schools as well as in out-of-school settings. Over the last ten years, the number of states in the US including engineering in their K-12 standards has tripled, and this trend will continue to grow with the adoption of the Next Generation Science Standards.The interest in pre-college engineering education stems from three different...