Agujeros negros (Black Holes)

For many years, people believed there were nine planets that orbited the sun. Now we say there are eight. What happened to the ninth planet, Pluto? What are the different planets like? What exactly makes a planet a planet? These are the many intriguing questions answered with this high-interest book, crafted to be accessible for readers of all levels. Young astronomers will be especially fascinated by the stunning photographs and the "Make the Grade" fact boxes.

"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 sea giants face-to-face: The Archelon was similar to a turtle, but its shell was made of crossed rib bone covered in rubbery skin! The Mososaurs had huge pointy jaws and grew to be fifty feet long! The Ichthyosaurs looked a lot...

Nueva traducción, acompañada de un completo estudio introductorio y un amplio cuerpo de notas, de esta obra de madurez en la que Cicerón analiza cuestiones de ética filosófica que, a juicio de su autor, pueden ayudar al lector a hacer más llevadera la tempestuosa travesía de la vida.

Fruits and vegetables both come from plants. Fruits have seeds. Vegetables do not. Let’s learn more about fruits and vegetables. Paired to the fiction title Planting Seeds.

�Puedes creerlo? Han pasado 25 a�os desde que nuestro hombrecito con sombrero de copa primero parti� a ser un fen�meno en todo el mundo! Sin embargo, todav�a se ve con su rostro fresco como siempre! Aun as�, durante este tiempo, Wally aprendi� algunos trucos astutos y nuevos sobre el arte de desaparecer... Esta es una nueva edici�n de b�squeda cl�sica para celebrar, ahora con diab�licos rompecabezas y un nuevo y asombroso arte. Lleno de extras fant�sticos, cubierta con solapa espectacular, desplegables nunca-antes-visto, y una lista para marcar. Este libro nos trae el...