Scott Brazelton was going to build a treehouse for his three-year-old, Wyatt. But then he stumbled upon a YouTube video by Paul Gregg, an engineer who built his grandkids a backyard roller coaster, ...

Thrill seekers and amusement park lovers may live for the high-octane rush of launch roller coasters but most probably never consider how they actually work. Some would probably make the mistake of ...