Nonfiction apps and e-books can be excellent tools to supplement classroom learning or independent research. These four interactive offerings — three science, one poetry — engage young users as they educate.

Cute kid Sloan Graham, the bear-suit-clad main character of I Love Mountains, has a passionate interest in the titular landforms. Over nineteen interactive pages, she shares fascinating geological facts including the three different types of mountains, how plate tectonics form them over time, the largest mountains on Earth and Mars, and various flora and fauna found within mountain ecosystems. The simplicity of Amanda Joyce Bishop's textured collage art adds a playful sense of wonder to the scientific discussion. Basic animations (i.e. snow falling, clouds moving) and easy touchscreen activities push the app forward at the user's pace. (Forest Giant, 4–7 years)

Like any good discovery museum exhibit, the San Francisco Exploratorium's Color Uncovered invites users to experiment for themselves as they learn about color. The light spectrum, humans' and various animals' perception of color, color blending, and complementary colors are just a few of the seventeen topics covered. In keeping with the Exploratorium's philosophy that "having fun is an important part of the [learning] process," the text is casual and humorous, frequently highlighting facts that are bizarre or downright (delightfully) gross. Video and interactive opportunities enhance the engaging text and crisp visuals. (Exploratorium, 6–10 years)

Nothing beats seeing dino fossils in person, but the American Museum of Natural History's Dinosaurs lets you get close to the real thing. Double-tap anywhere on an amazing mosaic in the shape of a T-rex's skull to zoom in and see how individual images of fossils, scientists, dioramas, and archival photos — over a thousand — make it up. A simple three-button navigation at the bottom of the screen allows you to jump back to the full mosaic; read more about the fossils in the collection; and access "AMNH Extras" including museum information and Educators Guide PDFs. (AMNH, 6–10 years)

The Poetry App presents over one hundred poems from sixteen of the world's greatest poets such as W. H. Auden, Emily Dickinson, Robert Frost, Elizabeth Bishop, William Butler Yeats, and Sylvia Plath. Each poem available to read is paired with an audio recitation performed by one of thirty critically acclaimed performers — a veritable who's who of British thespian elite — including Ralph Fiennes, Helen McCrory, Juliet Stevenson, and Jeremy Irons. Introductions and essays by the late author Josephine Hart accompany various poems, providing context and some explication. A composition tool allows users to compose their own poetry if inspiration strikes. (Josephine Hart Poetry Foundation, 9–14 years)

From the May 2014 issue of Notes from the Horn Book.