For hundreds of years, textbooks have put a world of knowledge in the hands of students. Paper textbooks are expensive to produce and expensive for schools to buy. Nowadays information changes so quickly that some textbooks are out of date almost before they're published. And as books are passed along from one student to the next, they get more highlighted, dog-eared, tattered, and worn. It's no secret that paper textbooks are heavy. But what you may not know is that backpack weight is an increasing problem among kids. Studies show that heavy backpacks can lead to both chronic back pain and poor posture -- and many kids are carrying a quarter of their body weight in textbooks.  Today's students have grown up completely immersed in technology. iPod, iPad, computer -- these are the ways they interact with their world. They need a textbook made for the way they learn. iBooks textbooks on iPad offer a gorgeous, full-screen experience full of interactive diagrams, photos, and videos. No longer limited to static pictures to illustrate the text, now students can dive into an image with interactive captions, rotate a 3D object, or have the answer spring to life in a chapter review. They can flip through a book by simply sliding a finger along the bottom of the screen. Highlighting text, taking notes, searching for content, and finding definitions in the glossary are just as easy. And with all their books on a single iPad, students will have no problem carrying them wherever they go. McGraw-Hill, Pearson Education, and Houghton Mifflin Harcourt -- the publishers responsible for the majority of K-12 content in the US -- have created Multi-Touch textbooks available now from the iBookstore Which is the closed meaning of the word "tattered" ?
tored ragged thrown used