El libro de tus quince aos/ Your Sweet Fifteen Book

"Some things are so huge or so old that it's hard to wrap your mind around them. But what if we took these big, hard-to-imagine objects and events and compared them to things we can see, feel and touch? Instantly, we'd see our world in a whole new way." So begins this endlessly intriguing guide to better understanding all those really big ideas and numbers children come across on a regular basis. Author David J. Smith has found clever devices to scale down everything from time lines (the history of Earth compressed into one year), to quantities (all the wealth in the world divided into one...

An elementary introduction to the workings of the human body, the skeleton, skin, circulation, and nervous system.

Learn about power resources and new kinds of fuels made from plants that can help to preserve our environment for the future.

Los dioses griegos existen. Si miras alrededor, los verás todos los días, en todas partes: en los bancos del parque, en los pasillos del instituto, dentro de ti... No tienes más que leer estos poemas para descubrirlos.