¿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.

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.

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.

Computer science is all around us, at school, at home, and in the community. This book gives readers the essential tools they need to understand the computer science concept of testing. Brilliant color photographs and accessible text will engage readers and allow them to connect deeply with the concept. The computer science topic is paired with an age-appropriate curricular topic to deepen readers’ learning experience and show how testing works in the real world. In this book, a narrator freezes water to make ice and makes sure his process worked. This nonfiction title is paired with the...

La colección ESTRATEGIAS DE SUPERVIVENCIA recoge todas aquellas tretas, señuelos y actividades que desarrollan los animales y las plantas tanto para defenderse como para atacar, para sobrevivir en medios hostiles, para reproducirse con éxito entre los dep

In 1991, preparation for the construction of a new federal office building led to a startling discovery: a skeleton. Further excavation exposed the bones of 420 men, women, and children. This area of New York had been a burial ground set aside for both free and enslaved Africans during the 1600s and 1700s. It’s thought to be one of the most important archaeological discoveries of the 20th century. This noteworthy book—which includes sidebars, fact boxes, a timeline, and maps—fills in the gaps of history books, exposing much about what life was like in colonial New York for Africans.

Antes de que Kamala Harris se convirtiera en abogada, senadora y vicepresidenta de Estados Unidos, fue una niña a la que le encantaban los superhéroes. Y cuando los buscaba a su alrededor, ¡se sorprendía al encontrarlos en todas partes! Los había en su familia, entre sus amigos, incluso en su misma calle; los superhéroes estaban dondequiera que ella miraba. Y esos superhéroes le enseñaron que todo lo que se necesita para ser un superhéroe es dar lo mejor de ti. En esta motivadora y expresiva memoria, que va directa al corazón de los niños, Kamala Harris lleva a los lectores a...