¿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.

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.

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.

En este cuaderno aprenderás la ortografía de numerosas palabras que se escriben con v y h, y te ejercitarás en la ortografía de diversas sílabas trabadas y libres. También se estudian algunas reglas fundamentales del uso de las mayúsculas: en principio de escrito y después de punto.

La cultura medieval islámica ha dado figuras espléndidas. Omar Jayyam, poeta y filósofo, algebrista y astrónomo, es sin duda la más fascinante de todas. Su pensamiento fue heterodoxo, su saber inmenso, su obra variadísima. De lo que nos ha llegado de su poesía no siempre es fácil distinguir lo auténtico de lo apócrifo, y de lo que sabemos de su vida, la historia de la leyenda. Su más importante aportación algebraica, la resolución sistemática de las ecuaciones cúbicas cortando cónicas, se procurará poner al alcance de un lector moderno sin alterar las ideas de fondo.

Rhyming text is ideal for building phonemic awareness and phonics skills. This series uses delightful rhyming text and engaging photographs to introduce beginning readers to four common weather conditions. These books build the foundation for reading success and make learning about weather fun!

Bullying is a common phenomenon facing society today. Author Nora Rodr?guez puts forth hundreds of strategies, divided by age groups, to educate children on the concepts of solidarity, mutual respect and the importance of resolving conflicts in a positive manner. Only through the involvement of parents and teachers in the detection and prevention of school bullying, will bullied and bullies be able to trust in themselves and grow to become secure human beings.