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

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.

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.

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.

In AD 79, the residents of the booming Roman city of Pompeii were shocked when a nearby mountain exploded, releasing superhot ash, rock, and gas on the surrounding areas. What happens next is the extraordinary account of a volcano in action. Though the people who didn't flee Pompeii were doomed, the volcano preserved their remains, allowing us to better understand a fascinating time in the Roman Empire. Astonishing photographs of Pompeii, primary source records of the occurrence, and riveting text are just some highlights of this high-interest volume.

Te presentamos al Papa Francisco. Nacido como Jorge Mario Bergoglio en Buenos Aires, Argentina, el Papa Francisco es el primer papa de las Américas. ¡También es el primer papa en reemplazar a un papa que todavía vive! Aprende todo sobre el Sumo Pontífice en este libro para niños de Nivel 1, apropiado para los primeros pasos de lectura independiente o para una experiencia de lectura en voz alta.

Enter the world of bug builders! Bugs can build structures that are as complex as the ones that we build! Readers will learn about the amazing things tiny creatures such as silkworms and beetles can build in this inviting, Spanish-translated nonfiction title that features detailed photos, riveting facts, informational text, a glossary for vocabulary improvement, and a list of useful websites. This 6-Pack includes six copies of this title and a lesson plan.

Las calles de una ciudad están llenas de historia, curiosidades y viejas leyendas. Descubre todo lo que hay que saber sobre Valencia con esta divertida guía, pensada para que los jóvenes viajeros disfruten conociendo esta interesante ciudad. Además, encon