How do you draw a straight line? How do you determine if a circle is really round? These may sound like simple or even trivial mathematical problems, but to an engineer the answers can mean the difference between success and failure. How Round Is Your Circle? invites readers to explore many of the same fundamental questions that working engineers deal with every day--it's challenging, hands-on, and fun. John Bryant and Chris Sangwin illustrate how physical models are created from abstract mathematical ones. Using elementary geometry and trigonometry, they guide readers through paper-and-pencil reconstructions of mathematical problems and show them how to construct actual physical models themselves--directions included. It's an effective and entertaining way to explain how applied mathematics and engineering work together to solve problems, everything from keeping a piston aligned in its cylinder to ensuring that automotive driveshafts rotate smoothly. Intriguingly, checking the roundness of a manufactured object is trickier than one might think. When does the width of a saw blade affect an engineer's calculations--or, for that matter, the width of a physical line? When does a measurement need to be exact and when will an approximation suffice? Bryant and Sangwin tackle questions like these and enliven their discussions with many fascinating highlights from engineering history. Generously illustrated, How Round Is Your Circle? reveals some of the hidden complexities in everyday things.
Discover your inner child once again in this debut fantasy adventure for fans of Madeleine L'Engle, Diana Wynne Jones, and E. L. Konigsburg. When the unexpected moves in next door, anything can happen in Weave a Circle Round, Kari Maaren's debut in this YA-friendly fantasy adventure. Freddy doesn’t want people to think she’s weird. Her family makes that difficult, though: her deaf stepbrother Roland’s a major geek, and her genius little sister Mel’s training to be the next Sherlock Holmes. All Freddy wants is to survive high school. Then two extremely odd neighbors move in next door. Cuerva Lachance and Josiah definitely aren't normal. Neither is their house, which defies the laws of physics. Neither is Freddy’s situation, when she suddenly finds herself stuck thousands of years in the past with her very, very weird neighbors. And that’s only the beginning. “I adored this brilliant book from start to finish. It left me reeling with delight and I can't wait for the rest of the world to get as lost in its pages as I was.” —Charles de Lint “I'd have loved this book when I was twelve, and I love it now.” —Nebula, Hugo, and World Fantasy-Award winning author Jo Walton