Emma Teitgen, 12, thought the chemistry book her teacher recommended would make perfect bedside reading. Perfect because it might help her fall asleep.

Then she downloaded "The Elements: A Visual Exploration" to her iPad. Instead of making her drowsy, it blossomed in her hands. The 118 chemical elements, from hydrogen to ununoctium, came alive in vivid images that could be rotated with a swipe of the finger.

Tapping on link after link, Teitgen was soon engrossed in a world of atomic weights and crystal structures. Three hours later, the seventh-grader looked up to see that it was 11 p.m., way past her bedtime.

Article link