Building roller coasters would be a really fun job. Up, up, up, down down down, around, upside down! How do you make a ride that can scare people silly but be completely safe, loop them around and hang them upside down without anyone falling out or throwing up?  That much fun takes some pretty clever engineering, and here you can read all about it. See how the modern roller coaster evolved from some very silly early ones, and learn all the special vocabulary you will need if you are going to be a big roller coaster fan.  It is difficult to read while you are on a roller coaster, but when you come down again and want to give your brain some more fun, give this book a look.