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

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.

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.

Book Features: • Ages 4-8, Grades PreK-2 • 16 pages, 8 inches x 8 inches • Simple, patterned Spanish text with full-color pictures • Includes comprehension questions, writing prompts, and high frequency words • Graphic organizers and photo glossary included Gassed About Learning: In Listos para las Ciencias: ¿Dónde está el Gas?, preschoolers—second graders learn the science behind matter such as gas, and where it can be found! Science Made Fun: Gas is everywhere. Do you know where gas is? Young readers learn fascinating facts about matter such as gas! Build Reading Skills: This ...

What is work? You may think work is doing chores or going to a job, but you do work every time you move something from one place to another. With experiments that demonstrate these fundamental concepts, discover how you work, and how simple machines make doing work easier.

Este tomo te permitirá conocer mejor al canguro, un marsupial que sólo vive en Australia y Nueva Guinea. Las hembras de los canguros, como las de todos los marsupiales, poseen una bolsa o marsupio, en cuyo inteiror se amamantan las crías hasta que tienen ocho o diez meses. En este volumen se describen las diferentes variedades de canguro, desde el ualabi de cola corta, del tamaño de una rata grande, al canguro rojo, que mide más de dos metros de altura y pesa alrededor de setenta kilos.

Do you know why there are thirteen stripes and fifty stars on the American flag? Or how the American flag inspired Francis Scott Key to write "The Star Spangled Banner?" Find out the answers to these questions and more in The American Flag.