With a world full of monitors and electronic displays made with liquid crystals, light-emitting diodes and gas plasma, you probably don't think of paper as being a revolutionary display technology, but the Chinese invention of paper in 105 A.D. forever changed the way the world communicates. Without it, books might still be printed on silk scrolls that only the wealthy could afford, making literacy a rare skill.
Look around you: It would be nearly impossible to live one day without coming into contact with paper in some form. This year, the world will consume an estimated 280 million tons of paper, according to the National Association of Paper Merchants in England. That is equal to 56 trillion sheets of letter-size 20-pound bond paper. (See this question of the day on paper weight.)
For nearly 2,000 years, ink on paper was the only way to display words and images, and it still beats computer displays when it comes to portability and price. Paper also doesn't require an external power supply. Yet it does have some limitations: Once you've printed words on paper, those words cannot be changed without at least leaving some marks, and it is also difficult to carry around a large number of books.
Scientists are now close to developing a revolutionary technology that could replace paper, called electronic ink! In this edition of How Stuff Will Work, you will find out about how electronic ink is made, how it will allow you to carry a whole library in one book and how it could be used for cheaper computer displays.