¿Por qué hibernan los animales? (Why Animals Hibernate)

The rock cycle has been taking place for millions of years. However, geologists have only known about this phenomenon for about 300 years. Young terrestrial explorers are introduced to different types of rocks, where in the cycle these rocks fit, and where in Earth's layers each step takes place. Fact boxes provide readers with fun additional information. A diagram helps readers make sense of the new information they're learning.

When rocks change because of environmental conditions, the new rocks are called metamorphic rocks. A rock's chemical or physical makeup may change because of conditions such as temperature, stress, or pressure. Your readers will learn fascinating facts including where metamorphic rocks are most commonly found, the different types of metamorphism, and how metamorphic rocks are identified. Full-color photographs depict these rocks in nature. A helpful graphic organizer shows how these fascinating rocks form.

Although Earth is mostly made up of igneous and metamorphic rock, sedimentary rock covers about 75 percent of Earth's land surface. This means it's the most visible kind of rock on Earth. Sedimentary rocks form when sediment accumulates and compacts. Your readers will learn how sedimentary rocks form, the different types of sedimentary rocks, and how people use sedimentary rocks. Fun fact boxes provide readers with additional information. A helpful diagram illustrates how sedimentary rocks form.

This book introduces you to giraffes, including their size, diet and everyday behavior, which highlights differences between those in the wild and those living in a zoo habitat.

Todo el mundo sabe que Katherine Mansfield pasó sus últimos días en el Instituto Gurdjieff en Fontainebleau", asegura Orage, autor de esta gran entrevista. "Tuve muchas conversaciones con Katherine sobre este tema durante los años de nuestra relación y, en particular, durante los meses que precedieron a su muerte. Solía decir: ́Supongamos que lograra escribir tan bien como Shakespeare. Sería encantador, y ¿luego qué? Algo le falta al arte literario, aun en su forma más alta. ¡La literatura no basta! ́. Éste es un testimonio invaluable de dos grandes escritores, que no sólo...

There is a contest at a school to design a new playground. The students use blocks to build their models. As they build, they use three-dimensional shapes. Some students build a train out of blocks for the younger students to play on. Can you guess which three-dimensional shape they use for the train's wheels? Read to find out which design wins.

Heredero de la gran tradición norteamericana en narrativa de terror, que nace con E.A. Poe y pasa por H.P. Lovecraft, Stephen King ha logrado con sus obras una difusión jamás alcanzada por ningún otro autor en este género, dotándolo de una vitalidad envidiable. Danza Macabra (1981) es un lúcido y divertido ensayo, lleno de referencias a multitud de obras y jugosas anécdotas biográficas, que pretende dar respuesta a la paradoja esencial del aficionado a la ficción de terror: «¿Por qué hay personas dispuestas a pagar a cambio de sentirse extremadamente incómodas?» Y para abordar...