¿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.

Diamonds and salt are both minerals, but diamonds are more rare than salt. Curious readers will learn what physical and chemical conditions must be present for minerals to form. They'll discover how minerals are identified and how they are used in daily life. Informative and interesting text presents readers with this science content in a fun way. A graphic organizer shows how different minerals are identified and fact boxes provide readers with exciting supplementary information.

Los ecosistemas han ido transformándose a lo largo de los años de forma natural; sin embargo, en los últimos siglos, factores como la contaminación o la sobreexplotación de los recursos naturales han puesto en peligro la salud de nuestro planeta. ¿Quieres

La vida cristiana transcurre dentro de un contexto, y el nuestro es la postmodernidad, una de cuyas características es el cambio constante y acelerado que nos hace cada vez más difícil orientarnos para saber vivir como seguidores de Jesús en el mundo actual. «Líderes Posmo» nos acercará a diferentes personajes de la Biblia; veremos las situaciones y los retos a los que se tuvieron que enfrentar. Así nos daremos cuenta del increíble paralelo existente con la vida actual. De los principios que ellos llevaron a la práctica, obtendremos la sabiduría que necesitamos para vivir como...

“Dino” Don Lessem brings readers face-to-face with various dinosaur species, detailing their habitats, way of life and how they became extinct. An acclaimed dinosaur expert, Don Lessem has written more than 30 children’s books, writes a popular dinosaur column in Highlights magazine, and was an adviser for Jurassic Park. Take a trip through dinosaur time to meet these small dinosaurs face-to-face: Little Lesothosaurus was the length of a house cat! Epidendrosaurus could climb into trees like a squirrel! Liaoceratops had body armor and horns-and was only the size of a collie dog! Plus,...

Explains the basic science of flight, the problems of getting vehicles into the air, different types of engines, and aircraft design, and includes instructions for making aircraft models.