When it comes to learning about the building blocks of our universe, Theodore Gray's The Elements for iPad is the perfect gateway. It's comprehensive, covering every known element; each of which has its own entry, including applications, detailed properties, and interactive images and videos to explore.
It's sort of a must-have for any suite of educational apps, or for anyone with even the vaguest interest in science -- and now it has its very own companion app, picking up where it left off. Theodore Gray has taken The Elements and extended it with the logical next step: Molecules.
The iPad app (also available as a physical book, only without all the interactive bits) is, to be fair, a little less comprehensive; after all, when you have some 118 identified chemical elements, the number of combinations is astronomical.
"There is no catalog of all the molecules in the universe, and there can't be," Gray explains in the introduction to the app. "There may only be six different chess pieces, but it's out of the question to list all the ways of arranging them on a chess board."
Instead, Molecules provides an overview: Gray has chosen to write about the molecules he finds the most interesting, and that demonstrate deeper and broader connections binding them. It is not, he clarifies, a chemistry textbook, and you won't find inside a catalogue of compounds. Rather, it's a primer, an overview.
"It's a little of everything, put together not to be complete, but to be interesting," Gray wrote. "It will teach you something about how the world of chemistry works, and give you a sense of the scope of the subject."
The book is divided into chapters, each of which deals with a particular topic, such as types of molecules, or molecules that people hate for various reasons, or molecules that halt pain. And, like The Elements, it also includes interactive features.
These aren't just animations that you can move around and interact with, although there are plenty of those: there is also a gallery of 348 molecules, which you can stretch and manipulate with multi-touch gestures in 3D space, experimenting with their motion -- which is explained in a special chapter written especially for the app.
And, of course, it's every bit as beautiful as its predecessor. You can grab it from the iTunes app store for iPhone and iPad for $13.99 (AU$17.99 | £9.99), or the print edition from the Black Dog and Leventhal website.