How did somebody come up with the idea for bridges, skyscrapers, helicopters, and nightlights? How did people figure out how to build them? In 3D Engineering: Design and Build Your Own Prototypes, young readers tackle real-life engineering problems by figuring out real-life solutions. Kids apply science and math skills to create prototypes for bridges, instruments, alarms, and more. Prototypes are preliminary models used by engineers--and...